Rename all Steinhart-Hart references to B-param

The Steinhart-Hart equation was changed in code long ago to the
B-parameter equation. Rename references to it and the interface
accordingly. The `s-h` command is now `b-p`.

The reason the name "B-Parameter" equation was chosen over
"Beta-Parameter" was due to its easier searchability.

.gitignore

@@ -1,2 +1,5 @@
 target/
 result
+*.bin
+
+__pycache__/

README.md

@@ -45,7 +45,7 @@ There are several options for flashing Thermostat. DFU requires only a micro-USB
 
 ### dfu-util on Linux
 * Install the DFU USB tool (dfu-util).
-* Convert firmware from ELF to BIN: `arm-none-eabi-objcopy -O binary thermostat thermostat.bin` (you can skip this step if using the BIN from Hydra)
+* Convert firmware from ELF to BIN: `llvm-objcopy -O binary target/thumbv7em-none-eabihf/release/thermostat thermostat.bin` (you can skip this step if using the BIN from Hydra)
 * Connect to the Micro USB connector to Thermostat below the RJ45.
 * Add jumper to Thermostat v2.0 across 2-pin jumper adjacent to JTAG connector.
 * Cycle board power to put it in DFU update mode
@@ -84,9 +84,7 @@ invalidate the first line of input.
 
 ### Reading ADC input
 
-Set report mode to `on` for a continuous stream of input data.
+ADC input data is provided in reports. Query for the latest report with the command `report`. See the *Reports* section below.
-
-The scope of this setting is per TCP session.
 
 
 ### TCP commands
@@ -94,42 +92,41 @@ The scope of this setting is per TCP session.
 Send commands as simple text string terminated by `\n`. Responses are
 formatted as line-delimited JSON.
 
-| Syntax                           | Function                                                                      |
+| Syntax                                     | Function                                                                      |
-|----------------------------------|-------------------------------------------------------------------------------|
+|------------------------------------------- |-------------------------------------------------------------------------------|
-| `report`                         | Show current input                                                            |
+| `report`                                   | Show current input                                                            |
-| `report mode`                    | Show current report mode                                                      |
+| `pwm`                                      | Show current PWM settings                                                     |
-| `report mode <off/on>`           | Set report mode                                                               |
+| `pwm <0/1> max_i_pos <amp>`                | Set maximum positive output current, clamped to [0, 2]                        |
-| `pwm`                            | Show current PWM settings                                                     |
+| `pwm <0/1> max_i_neg <amp>`                | Set maximum negative output current, clamped to [0, 2]                        |
-| `pwm <0/1> max_i_pos <amp>`      | Set maximum positive output current                                           |
+| `pwm <0/1> max_v <volt>`                   | Set maximum output voltage, clamped to [0, 4]                                 |
-| `pwm <0/1> max_i_neg <amp>`      | Set maximum negative output current                                           |
+| `pwm <0/1> i_set <amp>`                    | Disengage PID, set fixed output current, clamped to [-2, 2]                   |
-| `pwm <0/1> max_v <volt>`         | Set maximum output voltage                                                    |
+| `pwm <0/1> polarity <normal/reversed>`     | Set output current polarity, with 'normal' being the front panel polarity     |
-| `pwm <0/1> i_set <amp>`          | Disengage PID, set fixed output current                                       |
+| `pwm <0/1> pid`                            | Let output current to be controlled by the PID                                |
-| `pwm <0/1> pid`                  | Let output current to be controlled by the PID                                |
+| `center <0/1> <volt>`                      | Set the MAX1968 0A-centerpoint to the specified fixed voltage                 |
-| `center <0/1> <volt>`            | Set the MAX1968 0A-centerpoint to the specified fixed voltage                 |
+| `center <0/1> vref`                        | Set the MAX1968 0A-centerpoint to measure from VREF                           |
-| `center <0/1> vref`              | Set the MAX1968 0A-centerpoint to measure from VREF                           |
+| `pid`                                      | Show PID configuration                                                        |
-| `pid`                            | Show PID configuration                                                        |
+| `pid <0/1> target <deg_celsius>`           | Set the PID controller target temperature                                     |
-| `pid <0/1> target <deg_celsius>` | Set the PID controller target temperature                                     |
+| `pid <0/1> kp <value>`                     | Set proportional gain                                                         |
-| `pid <0/1> kp <value>`           | Set proportional gain                                                         |
+| `pid <0/1> ki <value>`                     | Set integral gain                                                             |
-| `pid <0/1> ki <value>`           | Set integral gain                                                             |
+| `pid <0/1> kd <value>`                     | Set differential gain                                                         |
-| `pid <0/1> kd <value>`           | Set differential gain                                                         |
+| `pid <0/1> output_min <amp>`               | Set mininum output                                                            |
-| `pid <0/1> output_min <amp>`     | Set mininum output                                                            |
+| `pid <0/1> output_max <amp>`               | Set maximum output                                                            |
-| `pid <0/1> output_max <amp>`     | Set maximum output                                                            |
+| `b-p`                                      | Show B-Parameter equation parameters                                          |
-| `s-h`                            | Show Steinhart-Hart equation parameters                                       |
+| `b-p <0/1> <t0/b/r0> <value>`              | Set B-Parameter for a channel                                                 |
-| `s-h <0/1> <t0/b/r0> <value>`    | Set Steinhart-Hart parameter for a channel                                    |
+| `postfilter`                               | Show postfilter settings                                                      |
-| `postfilter`                     | Show postfilter settings                                                      |
+| `postfilter <0/1> off`                     | Disable postfilter                                                            |
-| `postfilter <0/1> off`           | Disable postfilter                                                            |
+| `postfilter <0/1> rate <rate>`             | Set postfilter output data rate                                               |
-| `postfilter <0/1> rate <rate>`   | Set postfilter output data rate                                               |
+| `load [0/1]`                               | Restore configuration for channel all/0/1 from flash                          |
-| `load [0/1]`                     | Restore configuration for channel all/0/1 from flash                          |
+| `save [0/1]`                               | Save configuration for channel all/0/1 to flash                               |
-| `save [0/1]`                     | Save configuration for channel all/0/1 to flash                               |
+| `reset`                                    | Reset the device                                                              |
-| `reset`                          | Reset the device                                                              |
+| `dfu`                                      | Reset device and enters USB device firmware update (DFU) mode                 |
-| `dfu`                            | Reset device and enters USB device firmware update (DFU) mode                 |
+| `ipv4 <X.X.X.X/L> [Y.Y.Y.Y]`               | Configure IPv4 address, netmask length, and optional default gateway          |
-| `ipv4 <X.X.X.X/L> [Y.Y.Y.Y]`     | Configure IPv4 address, netmask length, and optional default gateway          |
+| `fan`                                      | Show current fan settings and sensors' measurements                           |
-| `fan`                            | Show current fan settings and sensors' measurements                           |
+| `fan <value>`                              | Set fan power with values from 1 to 100                                       |
-| `fan <value>`                    | Set fan power with values from 1 to 100                                       |
+| `fan auto`                                 | Enable automatic fan speed control                                            |
-| `fan auto`                       | Enable automatic fan speed control                                            |
+| `fcurve <a> <b> <c>`                       | Set fan controller curve coefficients (see *Fan control* section)             |
-| `fcurve <a> <b> <c>`             | Set fan controller curve coefficients (see *Fan control* section)             |
+| `fcurve default`                           | Set fan controller curve coefficients to defaults (see *Fan control* section) |
-| `fcurve default`                 | Set fan controller curve coefficients to defaults (see *Fan control* section) |
+| `hwrev`                                    | Show hardware revision, and settings related to it                            |
-| `hwrev`                          | Show hardware revision, and settings related to it                            |
 
 
 ## USB
@@ -147,22 +144,22 @@ output will be truncated when USB buffers are full.
 
 Connect the thermistor with the SENS pins of the
 device. Temperature-depending resistance is measured by the AD7172
-ADC. To prepare conversion to a temperature, set the Beta parameters
+ADC. To prepare conversion to a temperature, set the parameters
-for the Steinhart-Hart equation.
+for the B-Parameter equation.
 
 Set the base temperature in degrees celsius for the channel 0 thermistor:
 ```
-s-h 0 t0 20
+b-p 0 t0 20
 ```
 
 Set the resistance in Ohms measured at the base temperature t0:
 ```
-s-h 0 r0 10000
+b-p 0 r0 10000
 ```
 
 Set the Beta parameter:
 ```
-s-h 0 b 3800
+b-p 0 b 3800
 ```
 
 ### 50/60 Hz filtering
@@ -186,6 +183,8 @@ postfilter rate can be tuned with the `postfilter` command.
 
 When using a TEC module with the Thermostat, the Thermostat expects the thermal load (where the thermistor is located) to cool down with a positive software current set point, and heat up with a negative current set point.
 
+If the Thermostat is used for temperature control with the Sinara 5432 DAC "Zotino", and is connected via an IDC cable, the TEC polarity may need to be reversed with the `pwm <ch> polarity reversed` TCP command.
+
 Testing heat flow direction with a low set current is recommended before installation of the TEC module.
 
 ### Limits
@@ -251,8 +250,7 @@ pwm 0 pid
 
 ## Reports
 
-Use the bare `report` command to obtain a single report. Enable
+Use the bare `report` command to obtain a single report. Reports are JSON objects
-continuous reporting with `report mode on`. Reports are JSON objects
 with the following keys.
 
 | Key            | Unit            | Description                                          |
@@ -261,10 +259,9 @@ with the following keys.
 | `time`         | Seconds         | Temperature measurement time                         |
 | `adc`          | Volts           | AD7172 input                                         |
 | `sens`         | Ohms            | Thermistor resistance derived from `adc`             |
-| `temperature`  | Degrees Celsius | Steinhart-Hart conversion result derived from `sens` |
+| `temperature`  | Degrees Celsius | B-Parameter conversion result derived from `sens`    |
 | `pid_engaged`  | Boolean         | `true` if in closed-loop mode                        |
 | `i_set`        | Amperes         | TEC output current                                   |
-| `vref`         | Volts           | MAX1968 VREF (1.5 V)                                 |
 | `dac_value`    | Volts           | AD5680 output derived from `i_set`                   |
 | `dac_feedback` | Volts           | ADC measurement of the AD5680 output                 |
 | `i_tec`        | Volts           | MAX1968 TEC current monitor                          |
@@ -272,18 +269,19 @@ with the following keys.
 | `tec_u_meas`   | Volts           | Measurement of the voltage across the TEC            |
 | `pid_output`   | Amperes         | PID control output                                   |
 
+Note: With Thermostat v2 and below, the voltage and current readouts `i_tec` and `tec_i` are noisy without the hardware fix shown in [this PR][https://git.m-labs.hk/M-Labs/thermostat/pulls/105].
+
 ## PID Tuning
 
 The thermostat implements a PID control loop for each of the TEC channels, more details on setting up the PID control loop can be found [here](./doc/PID%20tuning.md).
 
 ## Fan control
 
-Fan control is available for the thermostat revisions with integrated fan system. For this purpose four commands are available:
+Fan control commands are available for thermostat revisions with an integrated fan system:
 1. `fan` - show fan stats: `fan_pwm`, `abs_max_tec_i`, `auto_mode`, `k_a`, `k_b`, `k_c`.
-2. `fan auto` - enable auto speed controller mode, which correlates with fan curve `fcurve`.
+2. `fan auto` - enable auto speed controller mode, where fan speed is controlled by the fan curve `fcurve`.
-3. `fan <value>` - set the fan power with the value from `1` to `100` and disable auto mode. There is no way to disable the fan.
+3. `fan <value>` - set the fan power with the value from `1` to `100` and disable auto mode. There is no way to completely disable the fan.
 Please note that power doesn't correlate with the actual speed linearly.
-4. `fcurve <a> <b> <c>` - set coefficients of the controlling curve `a*x^2 + b*x + c`, where `x` is `abs_max_tec_i/MAX_TEC_I`, 
+4. `fcurve <a> <b> <c>` - set coefficients of the controlling curve `a*x^2 + b*x + c`, where `x` is `abs_max_tec_i/MAX_TEC_I`, a normalized value in range [0,1],
-i.e. receives values from 0 to 1 linearly tied to the maximum current. The controlling curve should produce values from 0 to 1,
+i.e. the (linear) proportion of current output capacity used, on the channel with the largest current flow. The controlling curve is also clamped to [0,1].
-as below and beyond values would be substituted by 0 and 1 respectively.
+5. `fcurve default` - restore fan curve coefficients to defaults: `a = 1.0, b = 0.0, c = 0.0`.
-5. `fcurve default` - restore fan curve settings to defaults: `a = 1.0, b = 0.0, c = 0.0`.

flake.lock

@@ -1,41 +1,45 @@
 {
   "nodes": {
-    "mozilla-overlay": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1690536331,
-        "narHash": "sha256-aRIf2FB2GTdfF7gl13WyETmiV/J7EhBGkSWXfZvlxcA=",
-        "owner": "mozilla",
-        "repo": "nixpkgs-mozilla",
-        "rev": "db89c8707edcffefcd8e738459d511543a339ff5",
-        "type": "github"
-      },
-      "original": {
-        "owner": "mozilla",
-        "repo": "nixpkgs-mozilla",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1691421349,
+        "lastModified": 1722791413,
-        "narHash": "sha256-RRJyX0CUrs4uW4gMhd/X4rcDG8PTgaaCQM5rXEJOx6g=",
+        "narHash": "sha256-rCTrlCWvHzMCNcKxPE3Z/mMK2gDZ+BvvpEVyRM4tKmU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "011567f35433879aae5024fc6ec53f2a0568a6c4",
+        "rev": "8b5b6723aca5a51edf075936439d9cd3947b7b2c",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-23.05",
+        "ref": "nixos-24.05",
         "repo": "nixpkgs",
         "type": "github"
       }
     },
     "root": {
       "inputs": {
-        "mozilla-overlay": "mozilla-overlay",
+        "nixpkgs": "nixpkgs",
-        "nixpkgs": "nixpkgs"
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1719281921,
+        "narHash": "sha256-LIBMfhM9pMOlEvBI757GOK5l0R58SRi6YpwfYMbf4yc=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "b6032d3a404d8a52ecfc8571ff0c26dfbe221d07",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -1,32 +1,25 @@
 {
   description = "Firmware for the Sinara 8451 Thermostat";
 
-  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-23.05;
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
-  inputs.mozilla-overlay = { url = github:mozilla/nixpkgs-mozilla; flake = false; };
+  inputs.rust-overlay = { 
+    url = "github:oxalica/rust-overlay";
+    inputs.nixpkgs.follows = "nixpkgs";
+  };
 
-  outputs = { self, nixpkgs, mozilla-overlay }:
+  outputs = { self, nixpkgs, rust-overlay }:
     let
-      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import mozilla-overlay) ]; };
+      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import rust-overlay) ]; };
-      rustManifest = pkgs.fetchurl {
-        url = "https://static.rust-lang.org/dist/2022-12-15/channel-rust-stable.toml";
-        hash = "sha256-S7epLlflwt0d1GZP44u5Xosgf6dRrmr8xxC+Ml2Pq7c=";
-      };
 
-      targets = [
+      rust = pkgs.rust-bin.stable."1.66.0".default.override {
-        "thumbv7em-none-eabihf"
+        extensions = [ "rust-src" ];
-      ];
+        targets = [ "thumbv7em-none-eabihf" ];
-      rustChannelOfTargets = _channel: _date: targets:
+      };
-        (pkgs.lib.rustLib.fromManifestFile rustManifest {
+      rustPlatform = pkgs.makeRustPlatform {
-          inherit (pkgs) stdenv lib fetchurl patchelf;
-          }).rust.override {
-          inherit targets;
-          extensions = ["rust-src"];
-        };
-      rust = rustChannelOfTargets "stable" null targets;
-      rustPlatform = pkgs.recurseIntoAttrs (pkgs.makeRustPlatform {
         rustc = rust;
         cargo = rust;
-      });
+      };
+
       thermostat = rustPlatform.buildRustPackage {
         name = "thermostat";
         version = "0.0.0";
@@ -54,24 +47,26 @@
         '';
 
         dontFixup = true;
+        auditable = false;
       };
     in {
       packages.x86_64-linux = {
         inherit thermostat;
+        default = thermostat;
       };
 
       hydraJobs = {
         inherit thermostat;
       };
 
-      devShell.x86_64-linux = pkgs.mkShell {
+      devShells.x86_64-linux.default = pkgs.mkShellNoCC {
         name = "thermostat-dev-shell";
-        buildInputs = with pkgs; [
+        packages = with pkgs; [
-          rust openocd dfu-util
+          rust llvm
+          openocd dfu-util rlwrap
           ] ++ (with python3Packages; [
             numpy matplotlib
           ]);
       };
-      defaultPackage.x86_64-linux = thermostat;
     };
 }

pytec/example.py

@@ -1,11 +1,11 @@
 from pytec.client import Client
 
 tec = Client() #(host="localhost", port=6667)
-tec.set_param("s-h", 1, "t0", 20)
+tec.set_param("b-p", 1, "t0", 20)
 print(tec.get_pwm())
 print(tec.get_pid())
 print(tec.get_pwm())
 print(tec.get_postfilter())
-print(tec.get_steinhart_hart())
+print(tec.get_b_parameter())
 for data in tec.report_mode():
     print(data)

pytec/pytec/client.py

@@ -1,6 +1,7 @@
 import socket
 import json
 import logging
+import time
 
 class CommandError(Exception):
     pass
@@ -15,7 +16,7 @@ class Client:
         pwm_report = self.get_pwm()
         for pwm_channel in pwm_report:
             for limit in ["max_i_neg", "max_i_pos", "max_v"]:
-                if pwm_channel[limit]["value"] == 0.0:
+                if pwm_channel[limit] == 0.0:
                     logging.warning("`{}` limit is set to zero on channel {}".format(limit, pwm_channel["channel"]))
 
     def _read_line(self):
@@ -52,16 +53,18 @@ class Client:
         Example::
             [{'channel': 0,
               'center': 'vref',
-              'i_set': {'max': 2.9802790335151985, 'value': -0.02002179650216762},
+              'i_set': -0.02002179650216762,
-              'max_i_neg': {'max': 3.0, 'value': 3.0},
+              'max_i_neg': 2.0,
-              'max_v': {'max': 5.988, 'value': 5.988},
+              'max_v': 3.988,
-              'max_i_pos': {'max': 3.0, 'value': 3.0}},
+              'max_i_pos': 2.0,
+              'polarity': 'normal',
              {'channel': 1,
               'center': 'vref',
-              'i_set': {'max': 2.9802790335151985, 'value': -0.02002179650216762},
+              'i_set': -0.02002179650216762,
-              'max_i_neg': {'max': 3.0, 'value': 3.0},
+              'max_i_neg': 2.0,
-              'max_v': {'max': 5.988, 'value': 5.988},
+              'max_v': 3.988,
-              'max_i_pos': {'max': 3.0, 'value': 3.0}}
+              'max_i_pos': 2.0}
+              'polarity': 'normal',
             ]
         """
         return self._get_conf("pwm")
@@ -89,14 +92,14 @@ class Client:
         """
         return self._get_conf("pid")
 
-    def get_steinhart_hart(self):
+    def get_b_parameter(self):
-        """Retrieve Steinhart-Hart parameters for resistance to temperature conversion
+        """Retrieve B-Parameter equation parameters for resistance to temperature conversion
 
         Example::
             [{'params': {'b': 3800.0, 'r0': 10000.0, 't0': 298.15}, 'channel': 0},
              {'params': {'b': 3800.0, 'r0': 10000.0, 't0': 298.15}, 'channel': 1}]
         """
-        return self._get_conf("s-h")
+        return self._get_conf("b-p")
 
     def get_postfilter(self):
         """Retrieve DAC postfilter configuration
@@ -126,9 +129,8 @@ class Client:
              'tec_u_meas': 2.5340000000000003,
              'pid_output': 2.067581958092247}
         """
-        self._command("report mode", "on")
-
         while True:
+            self._socket.sendall("report\n".encode('utf-8'))
             line = self._read_line()
             if not line:
                 break
@@ -136,6 +138,7 @@ class Client:
                 yield json.loads(line)
             except json.decoder.JSONDecodeError:
                 pass
+            time.sleep(0.05)
 
     def set_param(self, topic, channel, field="", value=""):
         """Set configuration parameters
@@ -143,7 +146,7 @@ class Client:
         Examples::
             tec.set_param("pwm", 0, "max_v", 2.0)
             tec.set_param("pid", 1, "output_max", 2.5)
-            tec.set_param("s-h", 0, "t0", 20.0)
+            tec.set_param("b-p", 0, "t0", 20.0)
             tec.set_param("center", 0, "vref")
             tec.set_param("postfilter", 1, 21)
 

src/b_parameter.rs

@@ -10,15 +10,15 @@ use uom::si::{
 };
 use serde::{Deserialize, Serialize};
 
-/// Steinhart-Hart equation parameters
+/// B-Parameter equation parameters
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct Parameters {
     /// Base temperature
     pub t0: ThermodynamicTemperature,
-    /// Base resistance
+    /// Thermistor resistance at base temperature
     pub r0: ElectricalResistance,
-    /// Beta
+    /// B, the average slope of the function ln R vs. 1/T
-    pub b: f64,
+    pub b: ThermodynamicTemperature,
 }
 
 impl Parameters {

src/channel.rs

@@ -24,7 +24,7 @@ pub struct Channel<C: ChannelPins> {
     pub vref_meas: ElectricPotential,
     pub shdn: C::Shdn,
     pub vref_pin: C::VRefPin,
-    pub itec_pin: C::ItecPin,
+    pub itec_pin: C::ITecPin,
     /// feedback from `dac` output
     pub dac_feedback_pin: C::DacFeedbackPin,
     pub tec_u_meas_pin: C::TecUMeasPin,

src/channel_state.rs

@@ -2,11 +2,13 @@ use smoltcp::time::{Duration, Instant};
 use uom::si::{
     f64::{
         ElectricPotential,
+        ElectricCurrent,
         ElectricalResistance,
         ThermodynamicTemperature,
         Time,
     },
     electric_potential::volt,
+    electric_current::ampere,
     electrical_resistance::ohm,
     thermodynamic_temperature::degree_celsius,
     time::millisecond,
@@ -14,8 +16,9 @@ use uom::si::{
 use crate::{
     ad7172,
     pid,
-    steinhart_hart as sh,
+    config::PwmLimits,
-    command_parser::CenterPoint,
+    b_parameter as bp,
+    command_parser::{CenterPoint, Polarity},
 };
 
 const R_INNER: f64 = 2.0 * 5100.0;
@@ -29,9 +32,12 @@ pub struct ChannelState {
     /// i_set 0A center point
     pub center: CenterPoint,
     pub dac_value: ElectricPotential,
+    pub i_set: ElectricCurrent,
+    pub pwm_limits: PwmLimits,
     pub pid_engaged: bool,
     pub pid: pid::Controller,
-    pub sh: sh::Parameters,
+    pub bp: bp::Parameters,
+    pub polarity: Polarity,
 }
 
 impl ChannelState {
@@ -44,9 +50,16 @@ impl ChannelState {
             adc_interval: Duration::from_millis(100),
             center: CenterPoint::Vref,
             dac_value: ElectricPotential::new::<volt>(0.0),
+            i_set: ElectricCurrent::new::<ampere>(0.0),
+            pwm_limits: PwmLimits {
+                max_v: 0.0,
+                max_i_pos: 0.0,
+                max_i_neg: 0.0,
+            },
             pid_engaged: false,
             pid: pid::Controller::new(pid::Parameters::default()),
-            sh: sh::Parameters::default(),
+            bp: bp::Parameters::default(),
+            polarity: Polarity::Normal,
         }
     }
 
@@ -92,7 +105,7 @@ impl ChannelState {
 
     pub fn get_temperature(&self) -> Option<ThermodynamicTemperature> {
         let r = self.get_sens()?;
-        let temperature = self.sh.get_temperature(r);
+        let temperature = self.bp.get_temperature(r);
         Some(temperature)
     }
 }

src/channels.rs

@@ -1,5 +1,6 @@
-use core::cmp::max_by;
+use core::marker::PhantomData;
 use heapless::{consts::U2, Vec};
+use num_traits::Zero;
 use serde::{Serialize, Serializer};
 use smoltcp::time::Instant;
 use stm32f4xx_hal::hal;
@@ -16,17 +17,45 @@ use crate::{
     ad7172,
     channel::{Channel, Channel0, Channel1},
     channel_state::ChannelState,
-    command_parser::{CenterPoint, PwmPin},
+    command_parser::{CenterPoint, PwmPin, Polarity},
     command_handler::JsonBuffer,
-    pins,
+    pins::{self, Channel0VRef, Channel1VRef},
-    steinhart_hart,
+    b_parameter,
 };
+use crate::timer::sleep;
+
+pub enum PinsAdcReadTarget {
+    VREF,
+    DacVfb,
+    ITec,
+    VTec,
+}
 
 pub const CHANNELS: usize = 2;
 pub const R_SENSE: f64 = 0.05;
-// DAC chip outputs 0-5v, which is then passed through a resistor dividor to provide 0-3v range
-const DAC_OUT_V_MAX: f64 = 3.0;
 
+// From design specs
+pub const MAX_TEC_I: ElectricCurrent = ElectricCurrent {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 2.0,
+};
+pub const MAX_TEC_V: ElectricPotential = ElectricPotential {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 4.0,
+};
+const MAX_TEC_I_DUTY_TO_CURRENT_RATE: ElectricCurrent = ElectricCurrent {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 1.0 / (10.0 * R_SENSE / 3.3),
+};
+// DAC chip outputs 0-5v, which is then passed through a resistor dividor to provide 0-3v range
+const DAC_OUT_V_MAX: ElectricPotential = ElectricPotential {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 3.0,
+};
 // TODO: -pub
 pub struct Channels {
     channel0: Channel<Channel0>,
@@ -98,7 +127,7 @@ impl Channels {
     pub fn get_center(&mut self, channel: usize) -> ElectricPotential {
         match self.channel_state(channel).center {
             CenterPoint::Vref =>
-                self.read_vref(channel),
+                self.adc_read(channel, PinsAdcReadTarget::VREF, 8),
             CenterPoint::Override(center_point) =>
                 ElectricPotential::new::<volt>(center_point.into()),
         }
@@ -111,16 +140,13 @@ impl Channels {
     }
 
     pub fn get_i(&mut self, channel: usize) -> ElectricCurrent {
-        let center_point = self.get_center(channel);
+        let i_set = self.channel_state(channel).i_set;
-        let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
+        i_set
-        let voltage = self.get_dac(channel);
-        let i_tec = (voltage - center_point) / (10.0 * r_sense);
-        i_tec
     }
 
     /// i_set DAC
     fn set_dac(&mut self, channel: usize, voltage: ElectricPotential) -> ElectricPotential {
-        let value = ((voltage / ElectricPotential::new::<volt>(DAC_OUT_V_MAX)).get::<ratio>() * (ad5680::MAX_VALUE as f64)) as u32 ;
+        let value = ((voltage / DAC_OUT_V_MAX).get::<ratio>() * (ad5680::MAX_VALUE as f64)) as u32 ;
         match channel {
             0 => self.channel0.dac.set(value).unwrap(),
             1 => self.channel1.dac.set(value).unwrap(),
@@ -130,7 +156,13 @@ impl Channels {
         voltage
     }
 
-    pub fn set_i(&mut self, channel: usize, i_tec: ElectricCurrent) -> ElectricCurrent {
+    pub fn set_i(&mut self, channel: usize, i_set: ElectricCurrent) -> ElectricCurrent {
+        let i_set = i_set.min(MAX_TEC_I).max(-MAX_TEC_I);
+        self.channel_state(channel).i_set = i_set;
+        let negate = match self.channel_state(channel).polarity {
+            Polarity::Normal => 1.0,
+            Polarity::Reversed => -1.0,
+        };
         let vref_meas = match channel.into() {
             0 => self.channel0.vref_meas,
             1 => self.channel1.vref_meas,
@@ -138,109 +170,111 @@ impl Channels {
         };
         let center_point = vref_meas;
         let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
-        let voltage = i_tec * 10.0 * r_sense + center_point;
+        let voltage = negate * i_set * 10.0 * r_sense + center_point;
         let voltage = self.set_dac(channel, voltage);
-        let i_tec = (voltage - center_point) / (10.0 * r_sense);
+        let i_set = negate * (voltage - center_point) / (10.0 * r_sense);
-        i_tec
+        i_set
     }
 
-    pub fn read_dac_feedback(&mut self, channel: usize) -> ElectricPotential {
+    /// AN4073: ADC Reading Dispersion can be reduced through Averaging
+    pub fn adc_read(&mut self, channel: usize, adc_read_target: PinsAdcReadTarget, avg_pt: u16) -> ElectricPotential {
+        let mut sample: u32 = 0;
         match channel {
             0 => {
-                let sample = self.pins_adc.convert(
+                sample = match adc_read_target {
-                    &self.channel0.dac_feedback_pin,
+                    PinsAdcReadTarget::VREF => {
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
+                        match &self.channel0.vref_pin {
-                );
+                            Channel0VRef::Analog(vref_pin) => {
-                let mv = self.pins_adc.sample_to_millivolts(sample);
+                                for _ in (0..avg_pt).rev() {
+                                    sample += self
+                                        .pins_adc
+                                        .convert(vref_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                        as u32;
+                                }
+                                sample / avg_pt as u32
+                            },
+                            Channel0VRef::Disabled(_) => {2048 as u32}
+                        }
+                    }
+                    PinsAdcReadTarget::DacVfb => {
+                        for _ in (0..avg_pt).rev() {
+                            sample += self
+                                .pins_adc
+                                .convert(&self.channel0.dac_feedback_pin,stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                as u32;
+                        }
+                        sample / avg_pt as u32
+                    }
+                    PinsAdcReadTarget::ITec => {
+                        for _ in (0..avg_pt).rev() {
+                            sample += self
+                                .pins_adc
+                                .convert(&self.channel0.itec_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                as u32;
+                        }
+                        sample / avg_pt as u32
+                    }
+                    PinsAdcReadTarget::VTec => {
+                        for _ in (0..avg_pt).rev() {
+                            sample += self
+                                .pins_adc
+                                .convert(&self.channel0.tec_u_meas_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                as u32;
+                        }
+                        sample / avg_pt as u32
+                    }
+                };
+                let mv = self.pins_adc.sample_to_millivolts(sample as u16);
                 ElectricPotential::new::<millivolt>(mv as f64)
             }
             1 => {
-                let sample = self.pins_adc.convert(
+                sample = match adc_read_target {
-                    &self.channel1.dac_feedback_pin,
+                    PinsAdcReadTarget::VREF => {
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
+                        match &self.channel1.vref_pin {
-                );
+                            Channel1VRef::Analog(vref_pin) => {
-                let mv = self.pins_adc.sample_to_millivolts(sample);
+                                for _ in (0..avg_pt).rev() {
+                                    sample += self
+                                        .pins_adc
+                                        .convert(vref_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                        as u32;
+                                }
+                                sample / avg_pt as u32
+                            },
+                            Channel1VRef::Disabled(_) => {2048 as u32}
+                        }
+                    }
+                    PinsAdcReadTarget::DacVfb => {
+                        for _ in (0..avg_pt).rev() {
+                            sample += self
+                                .pins_adc
+                                .convert(&self.channel1.dac_feedback_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                as u32;
+                        }
+                        sample / avg_pt as u32
+                    }
+                    PinsAdcReadTarget::ITec => {
+                        for _ in (0..avg_pt).rev() {
+                            sample += self
+                                .pins_adc
+                                .convert(&self.channel1.itec_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                as u32;
+                        }
+                        sample / avg_pt as u32
+                    }
+                    PinsAdcReadTarget::VTec => {
+                        for _ in (0..avg_pt).rev() {
+                            sample += self
+                                .pins_adc
+                                .convert(&self.channel1.tec_u_meas_pin, stm32f4xx_hal::adc::config::SampleTime::Cycles_480)
+                                as u32;
+                        }
+                        sample / avg_pt as u32
+                    }
+                };
+                let mv = self.pins_adc.sample_to_millivolts(sample as u16);
                 ElectricPotential::new::<millivolt>(mv as f64)
             }
-            _ => unreachable!(),
+            _ => unreachable!()
-        }
-    }
-
-    pub fn read_dac_feedback_until_stable(&mut self, channel: usize, tolerance: ElectricPotential) -> ElectricPotential {
-        let mut prev = self.read_dac_feedback(channel);
-        loop {
-            let current = self.read_dac_feedback(channel);
-            if (current - prev).abs() < tolerance {
-                return current;
-            }
-            prev = current;
-        }
-    }
-
-    pub fn read_itec(&mut self, channel: usize) -> ElectricPotential {
-        match channel {
-            0 => {
-                let sample = self.pins_adc.convert(
-                    &self.channel0.itec_pin,
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
-                ElectricPotential::new::<millivolt>(mv as f64)
-            }
-            1 => {
-                let sample = self.pins_adc.convert(
-                    &self.channel1.itec_pin,
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
-                ElectricPotential::new::<millivolt>(mv as f64)
-            }
-            _ => unreachable!(),
-        }
-    }
-
-    /// should be 1.5V
-    pub fn read_vref(&mut self, channel: usize) -> ElectricPotential {
-        match channel {
-            0 => {
-                let sample = self.pins_adc.convert(
-                    &self.channel0.vref_pin,
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
-                ElectricPotential::new::<millivolt>(mv as f64)
-            }
-            1 => {
-                let sample = self.pins_adc.convert(
-                    &self.channel1.vref_pin,
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
-                ElectricPotential::new::<millivolt>(mv as f64)
-            }
-            _ => unreachable!(),
-        }
-    }
-
-    pub fn read_tec_u_meas(&mut self, channel: usize) -> ElectricPotential {
-        match channel {
-            0 => {
-                let sample = self.pins_adc.convert(
-                    &self.channel0.tec_u_meas_pin,
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
-                ElectricPotential::new::<millivolt>(mv as f64)
-            }
-            1 => {
-                let sample = self.pins_adc.convert(
-                    &self.channel1.tec_u_meas_pin,
-                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
-                ElectricPotential::new::<millivolt>(mv as f64)
-            }
-            _ => unreachable!(),
         }
     }
 
@@ -270,8 +304,7 @@ impl Channels {
         let mut start_value = 1;
         let mut best_error = ElectricPotential::new::<volt>(100.0);
 
-        for step in (0..18).rev() {
+        for step in (5..18).rev() {
-            let mut prev_value = start_value;
             for value in (start_value..=ad5680::MAX_VALUE).step_by(1 << step) {
                 match channel {
                     0 => {
@@ -282,24 +315,23 @@ impl Channels {
                     }
                     _ => unreachable!(),
                 }
+                sleep(10);
 
-                let dac_feedback = self.read_dac_feedback_until_stable(channel, ElectricPotential::new::<volt>(0.001));
+                let dac_feedback = self.adc_read(channel, PinsAdcReadTarget::DacVfb, 64);
                 let error = target_voltage - dac_feedback;
                 if error < ElectricPotential::new::<volt>(0.0) {
                     break;
                 } else if error < best_error {
                     best_error = error;
-                    start_value = prev_value;
+                    start_value = value;
 
-                    let vref = (value as f64 / ad5680::MAX_VALUE as f64) * ElectricPotential::new::<volt>(DAC_OUT_V_MAX);
+                    let vref = (value as f64 / ad5680::MAX_VALUE as f64) * DAC_OUT_V_MAX;
                     match channel {
                         0 => self.channel0.vref_meas = vref,
                         1 => self.channel1.vref_meas = vref,
                         _ => unreachable!(),
                     }
                 }
-
-                prev_value = value;
             }
         }
 
@@ -325,58 +357,30 @@ impl Channels {
         }
     }
 
-    fn get_pwm(&self, channel: usize, pin: PwmPin) -> f64 {
-        fn get<P: hal::PwmPin<Duty=u16>>(pin: &P) -> f64 {
-            let duty = pin.get_duty();
-            let max = pin.get_max_duty();
-            duty as f64 / (max as f64)
-        }
-        match (channel, pin) {
-            (_, PwmPin::ISet) =>
-                panic!("i_set is no pwm pin"),
-            (0, PwmPin::MaxIPos) =>
-                get(&self.pwm.max_i_pos0),
-            (0, PwmPin::MaxINeg) =>
-                get(&self.pwm.max_i_neg0),
-            (0, PwmPin::MaxV) =>
-                get(&self.pwm.max_v0),
-            (1, PwmPin::MaxIPos) =>
-                get(&self.pwm.max_i_pos1),
-            (1, PwmPin::MaxINeg) =>
-                get(&self.pwm.max_i_neg1),
-            (1, PwmPin::MaxV) =>
-                get(&self.pwm.max_v1),
-            _ =>
-                unreachable!(),
-        }
-    }
-
     pub fn get_max_v(&mut self, channel: usize) -> ElectricPotential {
-        let max = 4.0 * ElectricPotential::new::<volt>(3.3);
+        ElectricPotential::new::<volt>(self.channel_state(channel).pwm_limits.max_v)
-        let duty = self.get_pwm(channel, PwmPin::MaxV);
-        duty * max
     }
 
-    pub fn get_max_i_pos(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
+    pub fn get_max_i_pos(&mut self, channel: usize) -> ElectricCurrent {
-        let max = ElectricCurrent::new::<ampere>(3.0);
+        ElectricCurrent::new::<ampere>(self.channel_state(channel).pwm_limits.max_i_pos)
-        let duty = self.get_pwm(channel, PwmPin::MaxIPos);
-        (duty * max, max)
     }
 
-    pub fn get_max_i_neg(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
+    pub fn get_max_i_neg(&mut self, channel: usize) -> ElectricCurrent {
-        let max = ElectricCurrent::new::<ampere>(3.0);
+        ElectricCurrent::new::<ampere>(self.channel_state(channel).pwm_limits.max_i_neg)
-        let duty = self.get_pwm(channel, PwmPin::MaxINeg);
-        (duty * max, max)
     }
 
     // Get current passing through TEC
     pub fn get_tec_i(&mut self, channel: usize) -> ElectricCurrent {
-        (self.read_itec(channel) - self.read_vref(channel)) / ElectricalResistance::new::<ohm>(0.4)
+        let tec_i = (self.adc_read(channel, PinsAdcReadTarget::ITec, 16) - self.adc_read(channel, PinsAdcReadTarget::VREF, 16)) / ElectricalResistance::new::<ohm>(0.4);
+        match self.channel_state(channel).polarity {
+            Polarity::Normal => tec_i,
+            Polarity::Reversed => -tec_i,
+        }
     }
 
     // Get voltage across TEC
     pub fn get_tec_v(&mut self, channel: usize) -> ElectricPotential {
-        (self.read_tec_u_meas(channel) - ElectricPotential::new::<volt>(1.5)) * 4.0
+        (self.adc_read(channel, PinsAdcReadTarget::VTec, 16) - ElectricPotential::new::<volt>(1.5)) * 4.0
     }
 
     fn set_pwm(&mut self, channel: usize, pin: PwmPin, duty: f64) -> f64 {
@@ -408,28 +412,53 @@ impl Channels {
 
     pub fn set_max_v(&mut self, channel: usize, max_v: ElectricPotential) -> (ElectricPotential, ElectricPotential) {
         let max = 4.0 * ElectricPotential::new::<volt>(3.3);
+        let max_v = max_v.min(MAX_TEC_V).max(ElectricPotential::zero());
         let duty = (max_v / max).get::<ratio>();
         let duty = self.set_pwm(channel, PwmPin::MaxV, duty);
+        self.channel_state(channel).pwm_limits.max_v = max_v.get::<volt>();
         (duty * max, max)
     }
 
     pub fn set_max_i_pos(&mut self, channel: usize, max_i_pos: ElectricCurrent) -> (ElectricCurrent, ElectricCurrent) {
         let max = ElectricCurrent::new::<ampere>(3.0);
-        let duty = (max_i_pos / max).get::<ratio>();
+        let max_i_pos = max_i_pos.min(MAX_TEC_I).max(ElectricCurrent::zero());
-        let duty = self.set_pwm(channel, PwmPin::MaxIPos, duty);
+        let duty = (max_i_pos / MAX_TEC_I_DUTY_TO_CURRENT_RATE).get::<ratio>();
-        (duty * max, max)
+        let duty = match self.channel_state(channel).polarity {
+            Polarity::Normal => self.set_pwm(channel, PwmPin::MaxIPos, duty),
+            Polarity::Reversed => self.set_pwm(channel, PwmPin::MaxINeg, duty),
+        };
+        self.channel_state(channel).pwm_limits.max_i_pos = max_i_pos.get::<ampere>();
+        (duty * MAX_TEC_I_DUTY_TO_CURRENT_RATE, max)
     }
 
     pub fn set_max_i_neg(&mut self, channel: usize, max_i_neg: ElectricCurrent) -> (ElectricCurrent, ElectricCurrent) {
         let max = ElectricCurrent::new::<ampere>(3.0);
-        let duty = (max_i_neg / max).get::<ratio>();
+        let max_i_neg = max_i_neg.min(MAX_TEC_I).max(ElectricCurrent::zero());
-        let duty = self.set_pwm(channel, PwmPin::MaxINeg, duty);
+        let duty = (max_i_neg / MAX_TEC_I_DUTY_TO_CURRENT_RATE).get::<ratio>();
-        (duty * max, max)
+        let duty = match self.channel_state(channel).polarity {
+            Polarity::Normal => self.set_pwm(channel, PwmPin::MaxINeg, duty),
+            Polarity::Reversed => self.set_pwm(channel, PwmPin::MaxIPos, duty),
+        };
+        self.channel_state(channel).pwm_limits.max_i_neg = max_i_neg.get::<ampere>();
+        (duty * MAX_TEC_I_DUTY_TO_CURRENT_RATE, max)
+    }
+
+    pub fn set_polarity(&mut self, channel: usize, polarity: Polarity) {
+        if self.channel_state(channel).polarity != polarity {
+            let i_set = self.channel_state(channel).i_set;
+            let max_i_pos = self.get_max_i_pos(channel);
+            let max_i_neg = self.get_max_i_neg(channel);
+            self.channel_state(channel).polarity = polarity;
+
+            self.set_i(channel, i_set);
+            self.set_max_i_pos(channel, max_i_pos);
+            self.set_max_i_neg(channel, max_i_neg);
+        }
     }
 
     fn report(&mut self, channel: usize) -> Report {
         let i_set = self.get_i(channel);
-        let i_tec = self.read_itec(channel);
+        let i_tec = self.adc_read(channel, PinsAdcReadTarget::ITec, 16);
         let tec_i = self.get_tec_i(channel);
         let dac_value = self.get_dac(channel);
         let state = self.channel_state(channel);
@@ -445,7 +474,7 @@ impl Channels {
             pid_engaged: state.pid_engaged,
             i_set,
             dac_value,
-            dac_feedback: self.read_dac_feedback(channel),
+            dac_feedback: self.adc_read(channel, PinsAdcReadTarget::DacVfb, 1),
             i_tec,
             tec_i,
             tec_u_meas: self.get_tec_v(channel),
@@ -482,10 +511,11 @@ impl Channels {
         PwmSummary {
             channel,
             center: CenterPointJson(self.channel_state(channel).center.clone()),
-            i_set: (self.get_i(channel), ElectricCurrent::new::<ampere>(3.0)).into(),
+            i_set: self.get_i(channel),
-            max_v: (self.get_max_v(channel), ElectricPotential::new::<volt>(5.0)).into(),
+            max_v: self.get_max_v(channel),
-            max_i_pos: self.get_max_i_pos(channel).into(),
+            max_i_pos: self.get_max_i_pos(channel),
-            max_i_neg: self.get_max_i_neg(channel).into(),
+            max_i_neg: self.get_max_i_neg(channel),
+            polarity: PolarityJson(self.channel_state(channel).polarity.clone()),
         }
     }
 
@@ -511,23 +541,24 @@ impl Channels {
         serde_json_core::to_vec(&summaries)
     }
 
-    fn steinhart_hart_summary(&mut self, channel: usize) -> SteinhartHartSummary {
+    fn b_parameter_summary(&mut self, channel: usize) -> BParameterSummary {
-        let params = self.channel_state(channel).sh.clone();
+        let params = self.channel_state(channel).bp.clone();
-        SteinhartHartSummary { channel, params }
+        BParameterSummary { channel, params }
     }
 
-    pub fn steinhart_hart_summaries_json(&mut self) -> Result<JsonBuffer, serde_json_core::ser::Error> {
+    pub fn b_parameter_summaries_json(&mut self) -> Result<JsonBuffer, serde_json_core::ser::Error> {
         let mut summaries = Vec::<_, U2>::new();
         for channel in 0..CHANNELS {
-            let _ = summaries.push(self.steinhart_hart_summary(channel));
+            let _ = summaries.push(self.b_parameter_summary(channel));
         }
         serde_json_core::to_vec(&summaries)
     }
 
-    pub fn current_abs_max_tec_i(&mut self) -> f64 {
+    pub fn current_abs_max_tec_i(&mut self) -> ElectricCurrent {
-        max_by(self.get_tec_i(0).abs().get::<ampere>(),
+        (0..CHANNELS)
-               self.get_tec_i(1).abs().get::<ampere>(),
+            .map(|channel| self.get_tec_i(channel).abs())
-               |a, b| a.partial_cmp(b).unwrap_or(core::cmp::Ordering::Equal))
+            .max_by(|a, b| a.partial_cmp(b).unwrap_or(core::cmp::Ordering::Equal))
+            .unwrap()
     }
 }
 
@@ -566,15 +597,18 @@ impl Serialize for CenterPointJson {
     }
 }
 
-#[derive(Serialize)]
+pub struct PolarityJson(Polarity);
-pub struct PwmSummaryField<T: Serialize> {
-    value: T,
-    max: T,
-}
 
-impl<T: Serialize> From<(T, T)> for PwmSummaryField<T> {
+// used in JSON encoding, not for config
-    fn from((value, max): (T, T)) -> Self {
+impl Serialize for PolarityJson {
-        PwmSummaryField { value, max }
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(match self.0 {
+            Polarity::Normal => "normal",
+            Polarity::Reversed => "reversed",
+        })
     }
 }
 
@@ -582,10 +616,11 @@ impl<T: Serialize> From<(T, T)> for PwmSummaryField<T> {
 pub struct PwmSummary {
     channel: usize,
     center: CenterPointJson,
-    i_set: PwmSummaryField<ElectricCurrent>,
+    i_set: ElectricCurrent,
-    max_v: PwmSummaryField<ElectricPotential>,
+    max_v: ElectricPotential,
-    max_i_pos: PwmSummaryField<ElectricCurrent>,
+    max_i_pos: ElectricCurrent,
-    max_i_neg: PwmSummaryField<ElectricCurrent>,
+    max_i_neg: ElectricCurrent,
+    polarity: PolarityJson,
 }
 
 #[derive(Serialize)]
@@ -595,7 +630,7 @@ pub struct PostFilterSummary {
 }
 
 #[derive(Serialize)]
-pub struct SteinhartHartSummary {
+pub struct BParameterSummary {
     channel: usize,
-    params: steinhart_hart::Parameters,
+    params: b_parameter::Parameters,
 }

src/command_handler.rs

@@ -11,7 +11,8 @@ use super::{
         CenterPoint, 
         PidParameter, 
         PwmPin, 
-        ShParameter
+        BpParameter,
+        Polarity
     },
     ad7172,
     CHANNEL_CONFIG_KEY,
@@ -22,7 +23,6 @@ use super::{
     config::ChannelConfig,
     dfu,
     flash_store::FlashStore,
-    session::Session,
     FanCtrl,
     hw_rev::HWRev,
 };
@@ -87,16 +87,6 @@ fn send_line(socket: &mut TcpSocket, data: &[u8]) -> bool {
 
 impl Handler {
 
-    fn reporting(socket: &mut TcpSocket) -> Result<Handler, Error> {
-        send_line(socket, b"{}");
-        Ok(Handler::Handled)
-    }
-
-    fn show_report_mode(socket: &mut TcpSocket, session: &Session) -> Result<Handler, Error> {
-        let _ = writeln!(socket, "{{ \"report\": {:?} }}", session.reporting());
-        Ok(Handler::Handled)
-    }
-
     fn show_report(socket: &mut TcpSocket, channels: &mut Channels) -> Result<Handler, Error> {
         match channels.reports_json() {
             Ok(buf) => {
@@ -139,13 +129,13 @@ impl Handler {
         Ok(Handler::Handled)
     }
 
-    fn show_steinhart_hart(socket: &mut TcpSocket, channels: &mut Channels) -> Result<Handler, Error> {
+    fn show_b_parameter(socket: &mut TcpSocket, channels: &mut Channels) -> Result<Handler, Error> {
-        match channels.steinhart_hart_summaries_json() {
+        match channels.b_parameter_summaries_json() {
             Ok(buf) => {
                 send_line(socket, &buf);
             }
             Err(e) => {
-                error!("unable to serialize steinhart-hart summaries: {:?}", e);
+                error!("unable to serialize b parameter summaries: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
                 return Err(Error::ReportError);
             }
@@ -181,6 +171,12 @@ impl Handler {
         Ok(Handler::Handled)
     }
 
+    fn set_polarity(socket: &mut TcpSocket, channels: &mut Channels, channel: usize, polarity: Polarity) -> Result<Handler, Error> {
+        channels.set_polarity(channel, polarity);
+        send_line(socket, b"{}");
+        Ok(Handler::Handled)
+    }
+
     fn set_pwm (socket: &mut TcpSocket, channels: &mut Channels, channel: usize, pin: PwmPin, value: f64) -> Result<Handler, Error> {
         match pin {
             PwmPin::ISet => {
@@ -207,11 +203,11 @@ impl Handler {
     }
 
     fn set_center_point(socket: &mut TcpSocket, channels: &mut Channels, channel: usize, center: CenterPoint) -> Result<Handler, Error> {
-        let i_tec = channels.get_i(channel);
+        let i_set = channels.get_i(channel);
         let state = channels.channel_state(channel);
         state.center = center;
         if !state.pid_engaged {
-            channels.set_i(channel, i_tec);
+            channels.set_i(channel, i_set);
         }
         send_line(socket, b"{}");
         Ok(Handler::Handled)
@@ -238,13 +234,13 @@ impl Handler {
         Ok(Handler::Handled)
     }
 
-    fn set_steinhart_hart (socket: &mut TcpSocket, channels: &mut Channels, channel: usize, parameter: ShParameter, value: f64) -> Result<Handler, Error> {
+    fn set_b_parameter (socket: &mut TcpSocket, channels: &mut Channels, channel: usize, parameter: BpParameter, value: f64) -> Result<Handler, Error> {
-        let sh = &mut channels.channel_state(channel).sh;
+        let bp = &mut channels.channel_state(channel).bp;
-        use super::command_parser::ShParameter::*;
+        use super::command_parser::BpParameter::*;
         match parameter {
-            T0 => sh.t0 = ThermodynamicTemperature::new::<degree_celsius>(value),
+            T0 => bp.t0 = ThermodynamicTemperature::new::<degree_celsius>(value),
-            B => sh.b = value,
+            B => bp.b = value,
-            R0 => sh.r0 = ElectricalResistance::new::<ohm>(value),
+            R0 => bp.r0 = ElectricalResistance::new::<ohm>(value),
         }
         send_line(socket, b"{}");
         Ok(Handler::Handled)
@@ -345,7 +341,7 @@ impl Handler {
 
     fn set_fan(socket: &mut TcpSocket, fan_pwm: u32, fan_ctrl: &mut FanCtrl) -> Result<Handler, Error> {
         if !fan_ctrl.fan_available() {
-            send_line(socket, b"{ \"warning\": \"this thermostat doesn't have fan!\" }");
+            send_line(socket, b"{ \"warning\": \"this thermostat doesn't have a fan!\" }");
             return Ok(Handler::Handled);
         }
         fan_ctrl.set_auto_mode(false);
@@ -374,7 +370,7 @@ impl Handler {
 
     fn fan_auto(socket: &mut TcpSocket, fan_ctrl: &mut FanCtrl) -> Result<Handler, Error> {
         if !fan_ctrl.fan_available() {
-            send_line(socket, b"{ \"warning\": \"this thermostat doesn't have fan!\" }");
+            send_line(socket, b"{ \"warning\": \"this thermostat doesn't have a fan!\" }");
             return Ok(Handler::Handled);
         }
         fan_ctrl.set_auto_mode(true);
@@ -412,22 +408,21 @@ impl Handler {
         }
     }
 
-    pub fn handle_command(command: Command, socket: &mut TcpSocket, channels: &mut Channels, session: &Session, store: &mut FlashStore, ipv4_config: &mut Ipv4Config, fan_ctrl: &mut FanCtrl, hwrev: HWRev) -> Result<Self, Error> {
+    pub fn handle_command(command: Command, socket: &mut TcpSocket, channels: &mut Channels, store: &mut FlashStore, ipv4_config: &mut Ipv4Config, fan_ctrl: &mut FanCtrl, hwrev: HWRev) -> Result<Self, Error> {
         match command {
             Command::Quit => Ok(Handler::CloseSocket),
-            Command::Reporting(_reporting) => Handler::reporting(socket),            
-            Command::Show(ShowCommand::Reporting) => Handler::show_report_mode(socket, session),            
             Command::Show(ShowCommand::Input) => Handler::show_report(socket, channels),
             Command::Show(ShowCommand::Pid) => Handler::show_pid(socket, channels),
             Command::Show(ShowCommand::Pwm) => Handler::show_pwm(socket, channels),
-            Command::Show(ShowCommand::SteinhartHart) => Handler::show_steinhart_hart(socket, channels),
+            Command::Show(ShowCommand::BParameter) => Handler::show_b_parameter(socket, channels),
             Command::Show(ShowCommand::PostFilter) => Handler::show_post_filter(socket, channels),
             Command::Show(ShowCommand::Ipv4) => Handler::show_ipv4(socket, ipv4_config),
             Command::PwmPid { channel } => Handler::engage_pid(socket, channels, channel),
+            Command::PwmPolarity { channel, polarity } => Handler::set_polarity(socket, channels, channel, polarity),
             Command::Pwm { channel, pin, value } => Handler::set_pwm(socket, channels, channel, pin, value),
             Command::CenterPoint { channel, center } => Handler::set_center_point(socket, channels, channel, center),
             Command::Pid { channel, parameter, value } => Handler::set_pid(socket, channels, channel, parameter, value),
-            Command::SteinhartHart { channel, parameter, value } => Handler::set_steinhart_hart(socket, channels, channel, parameter, value),
+            Command::BParameter { channel, parameter, value } => Handler::set_b_parameter(socket, channels, channel, parameter, value),
             Command::PostFilter { channel, rate: None } => Handler::reset_post_filter(socket, channels, channel),
             Command::PostFilter { channel, rate: Some(rate) } => Handler::set_post_filter(socket, channels, channel, rate),
             Command::Load { channel } => Handler::load_channel(socket, channels, store, channel),

src/command_parser.rs

@@ -96,10 +96,9 @@ pub struct Ipv4Config {
 #[derive(Debug, Clone, PartialEq)]
 pub enum ShowCommand {
     Input,
-    Reporting,
     Pwm,
     Pid,
-    SteinhartHart,
+    BParameter,
     PostFilter,
     Ipv4,
 }
@@ -114,9 +113,9 @@ pub enum PidParameter {
     OutputMax,
 }
 
-/// Steinhart-Hart equation parameter
+/// B-Parameter equation parameter
 #[derive(Debug, Clone, PartialEq)]
-pub enum ShParameter {
+pub enum BpParameter {
     T0,
     B,
     R0,
@@ -136,6 +135,12 @@ pub enum CenterPoint {
     Override(f32),
 }
 
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum Polarity {
+    Normal,
+    Reversed,
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub enum Command {
     Quit,
@@ -148,7 +153,6 @@ pub enum Command {
     Reset,
     Ipv4(Ipv4Config),
     Show(ShowCommand),
-    Reporting(bool),
     /// PWM parameter setting
     Pwm {
         channel: usize,
@@ -159,6 +163,10 @@ pub enum Command {
     PwmPid {
         channel: usize,
     },
+    PwmPolarity {
+        channel: usize,
+        polarity: Polarity,
+    },
     CenterPoint {
         channel: usize,
         center: CenterPoint,
@@ -169,9 +177,9 @@ pub enum Command {
         parameter: PidParameter,
         value: f64,
     },
-    SteinhartHart {
+    BParameter {
         channel: usize,
-        parameter: ShParameter,
+        parameter: BpParameter,
         value: f64,
     },
     PostFilter {
@@ -233,12 +241,6 @@ fn float(input: &[u8]) -> IResult<&[u8], Result<f64, Error>> {
     Ok((input, result))
 }
 
-fn off_on(input: &[u8]) -> IResult<&[u8], bool> {
-    alt((value(false, tag("off")),
-         value(true, tag("on"))
-    ))(input)
-}
-
 fn channel(input: &[u8]) -> IResult<&[u8], usize> {
     map(one_of("01"), |c| (c as usize) - ('0' as usize))(input)
 }
@@ -246,24 +248,8 @@ fn channel(input: &[u8]) -> IResult<&[u8], usize> {
 fn report(input: &[u8]) -> IResult<&[u8], Command> {
     preceded(
         tag("report"),
-        alt((
+        // `report` - Report once
-            preceded(
+        value(Command::Show(ShowCommand::Input), end)
-                whitespace,
-                preceded(
-                    tag("mode"),
-                    alt((
-                        preceded(
-                            whitespace,
-                            // `report mode <on | off>` - Switch repoting mode
-                            map(off_on, Command::Reporting)
-                        ),
-                        // `report mode` - Show current reporting state
-                        value(Command::Show(ShowCommand::Reporting), end)
-                    ))
-                )),
-            // `report` - Report once
-            value(Command::Show(ShowCommand::Input), end)
-        ))
     )(input)
 }
 
@@ -321,6 +307,18 @@ fn pwm_pid(input: &[u8]) -> IResult<&[u8], ()> {
     value((), tag("pid"))(input)
 }
 
+fn pwm_polarity(input: &[u8]) -> IResult<&[u8], Polarity> {
+    preceded(
+        tag("polarity"),
+        preceded(
+            whitespace,
+            alt((value(Polarity::Normal, tag("normal")),
+                 value(Polarity::Reversed, tag("reversed"))
+            ))
+        )
+    )(input)
+}
+
 fn pwm(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
     let (input, _) = tag("pwm")(input)?;
     alt((
@@ -333,6 +331,10 @@ fn pwm(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
                     let (input, ()) = pwm_pid(input)?;
                     Ok((input, Ok(Command::PwmPid { channel })))
                 },
+                |input| {
+                    let (input, polarity) = pwm_polarity(input)?;
+                    Ok((input, Ok(Command::PwmPolarity { channel, polarity })))
+                },
                 |input| {
                     let (input, config) = pwm_setup(input)?;
                     match config {
@@ -400,31 +402,31 @@ fn pid(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
     ))(input)
 }
 
-/// `s-h <0-1> <parameter> <value>`
+/// `b-p <0-1> <parameter> <value>`
-fn steinhart_hart_parameter(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
+fn b_parameter_parameter(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
     let (input, channel) = channel(input)?;
     let (input, _) = whitespace(input)?;
     let (input, parameter) =
-        alt((value(ShParameter::T0, tag("t0")),
+        alt((value(BpParameter::T0, tag("t0")),
-             value(ShParameter::B, tag("b")),
+             value(BpParameter::B, tag("b")),
-             value(ShParameter::R0, tag("r0"))
+             value(BpParameter::R0, tag("r0"))
         ))(input)?;
     let (input, _) = whitespace(input)?;
     let (input, value) = float(input)?;
     let result = value
-        .map(|value| Command::SteinhartHart { channel, parameter, value });
+        .map(|value| Command::BParameter { channel, parameter, value });
     Ok((input, result))
 }
 
-/// `s-h` | `s-h <steinhart_hart_parameter>`
+/// `b-p` | `b-p <b_parameter_parameter>`
-fn steinhart_hart(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
+fn b_parameter(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
-    let (input, _) = tag("s-h")(input)?;
+    let (input, _) = tag("b-p")(input)?;
     alt((
         preceded(
             whitespace,
-            steinhart_hart_parameter
+            b_parameter_parameter
         ),
-        value(Ok(Command::Show(ShowCommand::SteinhartHart)), end)
+        value(Ok(Command::Show(ShowCommand::BParameter)), end)
     ))(input)
 }
 
@@ -594,7 +596,7 @@ fn command(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
          pwm,
          center_point,
          pid,
-         steinhart_hart,
+         b_parameter,
          postfilter,
          value(Ok(Command::Dfu), tag("dfu")),
          fan,
@@ -682,24 +684,6 @@ mod test {
         assert_eq!(command, Ok(Command::Show(ShowCommand::Input)));
     }
 
-    #[test]
-    fn parse_report_mode() {
-        let command = Command::parse(b"report mode");
-        assert_eq!(command, Ok(Command::Show(ShowCommand::Reporting)));
-    }
-
-    #[test]
-    fn parse_report_mode_on() {
-        let command = Command::parse(b"report mode on");
-        assert_eq!(command, Ok(Command::Reporting(true)));
-    }
-
-    #[test]
-    fn parse_report_mode_off() {
-        let command = Command::parse(b"report mode off");
-        assert_eq!(command, Ok(Command::Reporting(false)));
-    }
-
     #[test]
     fn parse_pwm_i_set() {
         let command = Command::parse(b"pwm 1 i_set 16383");
@@ -710,6 +694,15 @@ mod test {
         }));
     }
 
+    #[test]
+    fn parse_pwm_polarity() {
+        let command = Command::parse(b"pwm 0 polarity reversed");
+        assert_eq!(command, Ok(Command::PwmPolarity {
+            channel: 0,
+            polarity: Polarity::Reversed,
+        }));
+    }
+
     #[test]
     fn parse_pwm_pid() {
         let command = Command::parse(b"pwm 0 pid");
@@ -765,17 +758,17 @@ mod test {
     }
 
     #[test]
-    fn parse_steinhart_hart() {
+    fn parse_b_parameter() {
-        let command = Command::parse(b"s-h");
+        let command = Command::parse(b"b-p");
-        assert_eq!(command, Ok(Command::Show(ShowCommand::SteinhartHart)));
+        assert_eq!(command, Ok(Command::Show(ShowCommand::BParameter)));
     }
 
     #[test]
-    fn parse_steinhart_hart_set() {
+    fn parse_b_parameter_set() {
-        let command = Command::parse(b"s-h 1 t0 23.05");
+        let command = Command::parse(b"b-p 1 t0 23.05");
-        assert_eq!(command, Ok(Command::SteinhartHart {
+        assert_eq!(command, Ok(Command::BParameter {
             channel: 1,
-            parameter: ShParameter::T0,
+            parameter: BpParameter::T0,
             value: 23.05,
         }));
     }

src/config.rs

@@ -1,3 +1,4 @@
+use num_traits::Zero;
 use serde::{Serialize, Deserialize};
 use uom::si::{
     electric_potential::volt,
@@ -7,9 +8,9 @@ use uom::si::{
 use crate::{
     ad7172::PostFilter,
     channels::Channels,
-    command_parser::CenterPoint,
+    command_parser::{CenterPoint, Polarity},
     pid,
-    steinhart_hart,
+    b_parameter,
 };
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -18,7 +19,9 @@ pub struct ChannelConfig {
     pid: pid::Parameters,
     pid_target: f32,
     pid_engaged: bool,
-    sh: steinhart_hart::Parameters,
+    i_set: ElectricCurrent,
+    polarity: Polarity,
+    bp: b_parameter::Parameters,
     pwm: PwmLimits,
     /// uses variant `PostFilter::Invalid` instead of `None` to save space
     adc_postfilter: PostFilter,
@@ -33,12 +36,19 @@ impl ChannelConfig {
             .unwrap_or(PostFilter::Invalid);
 
         let state = channels.channel_state(channel);
+        let i_set = if state.pid_engaged { 
+            ElectricCurrent::zero() 
+        } else { 
+            state.i_set 
+        };
         ChannelConfig {
             center: state.center.clone(),
             pid: state.pid.parameters.clone(),
             pid_target: state.pid.target as f32,
             pid_engaged: state.pid_engaged,
-            sh: state.sh.clone(),
+            i_set,
+            polarity: state.polarity.clone(),
+            bp: state.bp.clone(),
             pwm,
             adc_postfilter,
         }
@@ -50,7 +60,7 @@ impl ChannelConfig {
         state.pid.parameters = self.pid.clone();
         state.pid.target = self.pid_target.into();
         state.pid_engaged = self.pid_engaged;
-        state.sh = self.sh.clone();
+        state.bp = self.bp.clone();
 
         self.pwm.apply(channels, channel);
 
@@ -59,21 +69,23 @@ impl ChannelConfig {
             adc_postfilter => Some(adc_postfilter),
         };
         let _ = channels.adc.set_postfilter(channel as u8, adc_postfilter);
+        let _ = channels.set_i(channel, self.i_set);
+        channels.set_polarity(channel, self.polarity.clone());
     }
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
-struct PwmLimits {
+pub struct PwmLimits {
-    max_v: f64,
+    pub max_v: f64,
-    max_i_pos: f64,
+    pub max_i_pos: f64,
-    max_i_neg: f64,
+    pub max_i_neg: f64,
 }
 
 impl PwmLimits {
     pub fn new(channels: &mut Channels, channel: usize) -> Self {
         let max_v = channels.get_max_v(channel);
-        let (max_i_pos, _) = channels.get_max_i_pos(channel);
+        let max_i_pos = channels.get_max_i_pos(channel);
-        let (max_i_neg, _) = channels.get_max_i_neg(channel);
+        let max_i_neg = channels.get_max_i_neg(channel);
         PwmLimits {
             max_v: max_v.get::<volt>(),
             max_i_pos: max_i_pos.get::<ampere>(),

src/fan_ctrl.rs

@@ -4,17 +4,18 @@ use stm32f4xx_hal::{
     pwm::{self, PwmChannels},
     pac::TIM8,
 };
-
+use uom::si::{
+    f64::ElectricCurrent,
+    electric_current::ampere,
+};
 use crate::{
     hw_rev::HWSettings,
     command_handler::JsonBuffer,
+    channels::MAX_TEC_I,
 };
 
 pub type FanPin = PwmChannels<TIM8, pwm::C4>;
 
-// as stated in the schematics
-const MAX_TEC_I: f32 = 3.0;
-
 const MAX_USER_FAN_PWM: f32 = 100.0;
 const MIN_USER_FAN_PWM: f32 = 1.0;
 
@@ -50,10 +51,10 @@ impl FanCtrl {
         fan_ctrl
     }
 
-    pub fn cycle(&mut self, abs_max_tec_i: f32) {
+    pub fn cycle(&mut self, abs_max_tec_i: ElectricCurrent) {
-        self.abs_max_tec_i = abs_max_tec_i;
+        self.abs_max_tec_i = abs_max_tec_i.get::<ampere>() as f32;
         if self.fan_auto && self.hw_settings.fan_available {
-            let scaled_current = self.abs_max_tec_i / MAX_TEC_I;
+            let scaled_current = self.abs_max_tec_i / MAX_TEC_I.get::<ampere>() as f32;
             // do not limit upper bound, as it will be limited in the set_pwm()
             let pwm = (MAX_USER_FAN_PWM * (scaled_current * (scaled_current * self.k_a + self.k_b) + self.k_c)) as u32;
             self.set_pwm(pwm);

src/main.rs

@@ -41,7 +41,7 @@ mod command_parser;
 use command_parser::Ipv4Config;
 mod timer;
 mod pid;
-mod steinhart_hart;
+mod b_parameter;
 mod channels;
 use channels::{CHANNELS, Channels};
 mod channel;
@@ -180,12 +180,9 @@ fn main() -> ! {
             loop {
                 let mut new_ipv4_config = None;
                 let instant = Instant::from_millis(i64::from(timer::now()));
-                let updated_channel = channels.poll_adc(instant);
+                channels.poll_adc(instant);
-                if let Some(channel) = updated_channel {
-                    server.for_each(|_, session| session.set_report_pending(channel.into()));
-                }
 
-                fan_ctrl.cycle(channels.current_abs_max_tec_i() as f32);
+                fan_ctrl.cycle(channels.current_abs_max_tec_i());
 
                 if channels.pid_engaged() {
                     leds.g3.on();
@@ -216,7 +213,7 @@ fn main() -> ! {
                                 // Do nothing and feed more data to the line reader in the next loop cycle.
                                 Ok(SessionInput::Nothing) => {}
                                 Ok(SessionInput::Command(command)) => {
-                                    match Handler::handle_command(command, &mut socket, &mut channels, session, &mut store, &mut ipv4_config, &mut fan_ctrl, hwrev) {
+                                    match Handler::handle_command(command, &mut socket, &mut channels, &mut store, &mut ipv4_config, &mut fan_ctrl, hwrev) {
                                         Ok(Handler::NewIPV4(ip)) => new_ipv4_config = Some(ip),                                
                                         Ok(Handler::Handled) => {},
                                         Ok(Handler::CloseSocket) => socket.close(),
@@ -231,19 +228,6 @@ fn main() -> ! {
                                 Err(_) =>
                                     socket.close(),
                             }
-                        } else if socket.can_send() {
-                            if let Some(channel) = session.is_report_pending() {
-                                match channels.reports_json() {
-                                    Ok(buf) => {
-                                        send_line(&mut socket, &buf[..]);
-                                        session.mark_report_sent(channel);
-                                    }
-                                    Err(e) => {
-                                        error!("unable to serialize report: {:?}", e);
-
-                                    }
-                                }
-                            }
                         }
                     });
                 } else {

src/pid.rs

@@ -54,15 +54,13 @@ impl Controller {
     //       + x0 * (kp + ki + kd)
     //       - x1 * (kp + 2kd)
     //       + x2 * kd
-    //       + kp * (u0 - u1)
     // y0  = clip(y0', ymin, ymax)
     pub fn update(&mut self, input: f64) -> f64 {
         
         let mut output: f64 = self.y1 - self.target * f64::from(self.parameters.ki)
                             + input * f64::from(self.parameters.kp + self.parameters.ki + self.parameters.kd)
                             - self.x1 * f64::from(self.parameters.kp + 2.0 * self.parameters.kd)
-                            + self.x2 * f64::from(self.parameters.kd)
+                            + self.x2 * f64::from(self.parameters.kd);
-                            + f64::from(self.parameters.kp) * (self.target - self.u1);
         if output < self.parameters.output_min.into() {
             output = self.parameters.output_min.into();
         }

src/pins.rs

@@ -61,27 +61,37 @@ pub trait ChannelPins {
     type DacSync: OutputPin;
     type Shdn: OutputPin;
     type VRefPin;
-    type ItecPin;
+    type ITecPin;
     type DacFeedbackPin;
     type TecUMeasPin;
 }
 
+pub enum Channel0VRef {
+    Analog(PA0<Analog>),
+    Disabled(PA0<Input<Floating>>),
+}
+
 impl ChannelPins for Channel0 {
     type DacSpi = Dac0Spi;
     type DacSync = PE4<Output<PushPull>>;
     type Shdn = PE10<Output<PushPull>>;
-    type VRefPin = PA0<Analog>;
+    type VRefPin = Channel0VRef;
-    type ItecPin = PA6<Analog>;
+    type ITecPin = PA6<Analog>;
     type DacFeedbackPin = PA4<Analog>;
     type TecUMeasPin = PC2<Analog>;
 }
 
+pub enum Channel1VRef {
+    Analog(PA3<Analog>),
+    Disabled(PA3<Input<Floating>>),
+}
+
 impl ChannelPins for Channel1 {
     type DacSpi = Dac1Spi;
     type DacSync = PF6<Output<PushPull>>;
     type Shdn = PE15<Output<PushPull>>;
-    type VRefPin = PA3<Analog>;
+    type VRefPin = Channel1VRef;
-    type ItecPin = PB0<Analog>;
+    type ITecPin = PB0<Analog>;
     type DacFeedbackPin = PA5<Analog>;
     type TecUMeasPin = PC3<Analog>;
 }
@@ -98,7 +108,7 @@ pub struct ChannelPinSet<C: ChannelPins> {
     pub dac_sync: C::DacSync,
     pub shdn: C::Shdn,
     pub vref_pin: C::VRefPin,
-    pub itec_pin: C::ItecPin,
+    pub itec_pin: C::ITecPin,
     pub dac_feedback_pin: C::DacFeedbackPin,
     pub tec_u_meas_pin: C::TecUMeasPin,
 }
@@ -150,13 +160,17 @@ impl Pins {
             gpioe.pe13, gpioe.pe14
         );
 
+        let hwrev = HWRev::detect_hw_rev(&HWRevPins {hwrev0: gpiod.pd0, hwrev1: gpiod.pd1,
+            hwrev2: gpiod.pd2, hwrev3: gpiod.pd3});
+        let hw_settings = hwrev.settings();
+
         let (dac0_spi, dac0_sync) = Self::setup_dac0(
             clocks, spi4,
             gpioe.pe2, gpioe.pe4, gpioe.pe6
         );
         let mut shdn0 = gpioe.pe10.into_push_pull_output();
         let _ = shdn0.set_low();
-        let vref0_pin = gpioa.pa0.into_analog();
+        let vref0_pin = if hwrev.major > 2 {Channel0VRef::Analog(gpioa.pa0.into_analog())} else {Channel0VRef::Disabled(gpioa.pa0)};
         let itec0_pin = gpioa.pa6.into_analog();
         let dac_feedback0_pin = gpioa.pa4.into_analog();
         let tec_u_meas0_pin = gpioc.pc2.into_analog();
@@ -176,7 +190,7 @@ impl Pins {
         );
         let mut shdn1 = gpioe.pe15.into_push_pull_output();
         let _ = shdn1.set_low();
-        let vref1_pin = gpioa.pa3.into_analog();
+        let vref1_pin = if hwrev.major > 2 {Channel1VRef::Analog(gpioa.pa3.into_analog())} else {Channel1VRef::Disabled(gpioa.pa3)};
         let itec1_pin = gpiob.pb0.into_analog();
         let dac_feedback1_pin = gpioa.pa5.into_analog();
         let tec_u_meas1_pin = gpioc.pc3.into_analog();
@@ -198,10 +212,6 @@ impl Pins {
             channel1,
         };
 
-        let hwrev = HWRev::detect_hw_rev(&HWRevPins {hwrev0: gpiod.pd0, hwrev1: gpiod.pd1,
-            hwrev2: gpiod.pd2, hwrev3: gpiod.pd3});
-        let hw_settings = hwrev.settings();
-
         let leds = Leds::new(gpiod.pd9, gpiod.pd10.into_push_pull_output(), gpiod.pd11.into_push_pull_output());
 
         let eeprom_scl = gpiob.pb8.into_alternate().set_open_drain();

src/session.rs

@@ -1,5 +1,4 @@
 use super::command_parser::{Command, Error as ParserError};
-use super::channels::CHANNELS;
 
 const MAX_LINE_LEN: usize = 64;
 
@@ -53,8 +52,6 @@ impl From<Result<Command, ParserError>> for SessionInput {
 
 pub struct Session {
     reader: LineReader,
-    reporting: bool,
-    report_pending: [bool; CHANNELS],
 }
 
 impl Default for Session {
@@ -67,43 +64,11 @@ impl Session {
     pub fn new() -> Self {
         Session {
             reader: LineReader::new(),
-            reporting: false,
-            report_pending: [false; CHANNELS],
         }
     }
 
     pub fn reset(&mut self) {
         self.reader = LineReader::new();
-        self.reporting = false;
-        self.report_pending = [false; CHANNELS];
-    }
-
-    pub fn reporting(&self) -> bool {
-        self.reporting
-    }
-
-    pub fn set_report_pending(&mut self, channel: usize) {
-        if self.reporting {
-            self.report_pending[channel] = true;
-        }
-    }
-
-    pub fn is_report_pending(&self) -> Option<usize> {
-        if ! self.reporting {
-            None
-        } else {
-            self.report_pending.iter()
-                .enumerate()
-                .fold(None, |result, (channel, report_pending)| {
-                    result.or_else(|| {
-                        if *report_pending { Some(channel) } else { None }
-                    })
-                })
-        }
-    }
-
-    pub fn mark_report_sent(&mut self, channel: usize) {
-        self.report_pending[channel] = false;
     }
 
     pub fn feed(&mut self, buf: &[u8]) -> (usize, SessionInput) {
@@ -114,12 +79,6 @@ impl Session {
             match line {
                 Some(line) => {
                     let command = Command::parse(&line);
-                    match command {
-                        Ok(Command::Reporting(reporting)) => {
-                            self.reporting = reporting;
-                        }
-                        _ => {}
-                    }
                     return (buf_bytes, command.into());
                 }
                 None => {}