MAX_TEC_I -> MAX_I

Names in the report make no sense, and expose implementation details.
Start simplifying the interface.

README.md

@@ -268,7 +268,7 @@ with the following keys.
 | `i_measured`   | Amperes         | Measured current passing through TEC           |
 | `v_measured`   | Volts           | Measured voltage across TEC                    |
 
-Note: With Thermostat v2 and below, the voltage and current readouts `i_tec` and `tec_i` are disabled and null due to faulty hardware that introduces a lot of noise in the signal.
+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
 

flake.lock

@@ -1,21 +1,5 @@
 {
   "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,
@@ -34,8 +18,28 @@
     },
     "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

@@ -2,31 +2,24 @@
   description = "Firmware for the Sinara 8451 Thermostat";
 
   inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-23.05;
-  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) ]; };
-      rustManifest = pkgs.fetchurl {
-        url = "https://static.rust-lang.org/dist/2022-12-15/channel-rust-stable.toml";
-        hash = "sha256-S7epLlflwt0d1GZP44u5Xosgf6dRrmr8xxC+Ml2Pq7c=";
-      };
+      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import rust-overlay) ]; };
 
-      targets = [
-        "thumbv7em-none-eabihf"
-      ];
-      rustChannelOfTargets = _channel: _date: targets:
-        (pkgs.lib.rustLib.fromManifestFile rustManifest {
-          inherit (pkgs) stdenv lib fetchurl patchelf;
-          }).rust.override {
-          inherit targets;
+      rust = pkgs.rust-bin.stable."1.66.0".default.override {
         extensions = [ "rust-src" ];
+        targets = [ "thumbv7em-none-eabihf" ];
       };
-      rust = rustChannelOfTargets "stable" null targets;
-      rustPlatform = pkgs.recurseIntoAttrs (pkgs.makeRustPlatform {
+      rustPlatform = pkgs.makeRustPlatform {
         rustc = rust;
         cargo = rust;
-      });
+      };
+
       thermostat = rustPlatform.buildRustPackage {
         name = "thermostat";
         version = "0.0.0";
@@ -58,21 +51,21 @@
     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 llvm
           openocd dfu-util
           ] ++ (with python3Packages; [
             numpy matplotlib
           ]);
       };
-      defaultPackage.x86_64-linux = thermostat;
     };
 }

src/channel_state.rs

@@ -1,9 +1,12 @@
 use crate::{ad7172, command_parser::CenterPoint, pid, steinhart_hart as sh};
 use smoltcp::time::{Duration, Instant};
 use uom::si::{
+    electric_current::ampere,
     electric_potential::volt,
     electrical_resistance::ohm,
-    f64::{ElectricPotential, ElectricalResistance, ThermodynamicTemperature, Time},
+    f64::{
+        ElectricCurrent, ElectricPotential, ElectricalResistance, ThermodynamicTemperature, Time,
+    },
     thermodynamic_temperature::degree_celsius,
     time::millisecond,
 };
@@ -19,6 +22,7 @@ pub struct ChannelState {
     /// i_set 0A center point
     pub center: CenterPoint,
     pub dac_value: ElectricPotential,
+    pub i_set: ElectricCurrent,
     pub pid_engaged: bool,
     pub pid: pid::Controller,
     pub sh: sh::Parameters,
@@ -34,6 +38,7 @@ 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),
             pid_engaged: false,
             pid: pid::Controller::new(pid::Parameters::default()),
             sh: sh::Parameters::default(),

src/channels.rs

@@ -4,10 +4,12 @@ use crate::{
     channel_state::ChannelState,
     command_handler::JsonBuffer,
     command_parser::{CenterPoint, PwmPin},
-    hw_rev, pins, steinhart_hart,
+    pins::{self, Channel0VRef, Channel1VRef},
+    steinhart_hart,
 };
-use core::cmp::max_by;
+use core::{cmp::max_by, marker::PhantomData};
 use heapless::{consts::U2, Vec};
+use num_traits::Zero;
 use serde::{Serialize, Serializer};
 use smoltcp::time::Instant;
 use stm32f4xx_hal::hal;
@@ -20,24 +22,46 @@ use uom::si::{
     thermodynamic_temperature::degree_celsius,
 };
 
+pub enum PinsAdcReadTarget {
+    VREF,
+    DacVfb,
+    ITec,
+    VTec,
+}
+
 pub const CHANNELS: usize = 2;
 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_I: ElectricCurrent = ElectricCurrent {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 2.0,
+};
+pub const MAX_TEC_V: ElectricPotential = ElectricPotential {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 4.0,
+};
+
+// 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<'a> {
+pub struct Channels {
     channel0: Channel<Channel0>,
     channel1: Channel<Channel1>,
     pub adc: ad7172::Adc<pins::AdcSpi, pins::AdcNss>,
     /// stm32f4 integrated adc
     pins_adc: pins::PinsAdc,
     pwm: pins::PwmPins,
-    hwrev: &'a hw_rev::HWRev,
 }
 
-impl<'a> Channels<'a> {
-    pub fn new(pins: pins::Pins, hwrev: &'a hw_rev::HWRev) -> Self {
+impl Channels {
+    pub fn new(pins: pins::Pins) -> Self {
         let mut adc = ad7172::Adc::new(pins.adc_spi, pins.adc_nss).unwrap();
         // Feature not used
         adc.set_sync_enable(false).unwrap();
@@ -61,7 +85,6 @@ impl<'a> Channels<'a> {
             adc,
             pins_adc,
             pwm,
-            hwrev,
         };
         for channel in 0..CHANNELS {
             channels.calibrate_dac_value(channel);
@@ -103,7 +126,7 @@ impl<'a> Channels<'a> {
     /// calculate the TEC i_set centerpoint
     pub fn get_center(&mut self, channel: usize) -> ElectricPotential {
         match self.channel_state(channel).center {
-            CenterPoint::Vref => self.read_vref(channel),
+            CenterPoint::Vref => self.adc_read(channel, PinsAdcReadTarget::VREF, 8),
             CenterPoint::Override(center_point) => {
                 ElectricPotential::new::<volt>(center_point.into())
             }
@@ -117,16 +140,13 @@ impl<'a> Channels<'a> {
     }
 
     pub fn get_i_set(&mut self, channel: usize) -> ElectricCurrent {
-        let center_point = self.get_center(channel);
-        let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
-        let voltage = self.get_dac(channel);
-        (voltage - center_point) / (10.0 * r_sense)
+        let i_set = self.channel_state(channel).i_set;
+        i_set
     }
 
     /// 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(),
@@ -137,6 +157,7 @@ impl<'a> Channels<'a> {
     }
 
     pub fn set_i(&mut self, channel: usize, i_set: ElectricCurrent) -> ElectricCurrent {
+        let i_set = i_set.min(MAX_I).max(-MAX_I);
         let vref_meas = match channel {
             0 => self.channel0.vref_meas,
             1 => self.channel1.vref_meas,
@@ -146,25 +167,108 @@ impl<'a> Channels<'a> {
         let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
         let voltage = i_set * 10.0 * r_sense + center_point;
         let voltage = self.set_dac(channel, voltage);
-        (voltage - center_point) / (10.0 * r_sense)
+        let i_set = (voltage - center_point) / (10.0 * r_sense);
+        self.channel_state(channel).i_set = i_set;
+        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 {
+                    PinsAdcReadTarget::VREF => match &self.channel0.vref_pin {
+                        Channel0VRef::Analog(vref_pin) => {
+                            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_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,
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
+                            ) 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 {
+                    PinsAdcReadTarget::VREF => match &self.channel1.vref_pin {
+                        Channel1VRef::Analog(vref_pin) => {
+                            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_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,
-                );
-                let mv = self.pins_adc.sample_to_millivolts(sample);
+                            ) 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!(),
@@ -176,9 +280,9 @@ impl<'a> Channels<'a> {
         channel: usize,
         tolerance: ElectricPotential,
     ) -> ElectricPotential {
-        let mut prev = self.read_dac_feedback(channel);
+        let mut prev = self.adc_read(channel, PinsAdcReadTarget::DacVfb, 1);
         loop {
-            let current = self.read_dac_feedback(channel);
+            let current = self.adc_read(channel, PinsAdcReadTarget::DacVfb, 1);
             if (current - prev).abs() < tolerance {
                 return current;
             }
@@ -186,73 +290,6 @@ impl<'a> Channels<'a> {
         }
     }
 
-    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!(),
-        }
-    }
-
     /// Calibrates the DAC output to match vref of the MAX driver to reduce zero-current offset of the MAX driver output.
     ///
     /// The thermostat DAC applies a control voltage signal to the CTLI pin of MAX driver chip to control its output current.
@@ -301,8 +338,7 @@ impl<'a> Channels<'a> {
                     best_error = error;
                     start_value = prev_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,
@@ -354,32 +390,35 @@ impl<'a> Channels<'a> {
         }
     }
 
-    pub fn get_max_v(&mut self, channel: usize) -> ElectricPotential {
+    pub fn get_max_v(&mut self, channel: usize) -> (ElectricPotential, ElectricPotential) {
         let max = 4.0 * ElectricPotential::new::<volt>(3.3);
         let duty = self.get_pwm(channel, PwmPin::MaxV);
-        duty * max
+        (duty * max, MAX_TEC_V)
     }
 
     pub fn get_max_i_pos(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
         let max = ElectricCurrent::new::<ampere>(3.0);
         let duty = self.get_pwm(channel, PwmPin::MaxIPos);
-        (duty * max, max)
+        (duty * max, MAX_I)
     }
 
     pub fn get_max_i_neg(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
         let max = ElectricCurrent::new::<ampere>(3.0);
         let duty = self.get_pwm(channel, PwmPin::MaxINeg);
-        (duty * max, max)
+        (duty * max, MAX_I)
     }
 
     // Measure current passing through TEC
     pub fn get_i_measured(&mut self, channel: usize) -> ElectricCurrent {
-        (self.read_itec(channel) - self.read_vref(channel)) / ElectricalResistance::new::<ohm>(0.4)
+        (self.adc_read(channel, PinsAdcReadTarget::ITec, 16)
+            - self.adc_read(channel, PinsAdcReadTarget::VREF, 16))
+            / ElectricalResistance::new::<ohm>(0.4)
     }
 
     // Measure voltage across TEC
     pub fn get_v_measured(&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 {
@@ -407,7 +446,7 @@ impl<'a> Channels<'a> {
         max_v: ElectricPotential,
     ) -> (ElectricPotential, ElectricPotential) {
         let max = 4.0 * ElectricPotential::new::<volt>(3.3);
-        let duty = (max_v / max).get::<ratio>();
+        let duty = (max_v.min(MAX_TEC_V).max(ElectricPotential::zero()) / max).get::<ratio>();
         let duty = self.set_pwm(channel, PwmPin::MaxV, duty);
         (duty * max, max)
     }
@@ -418,7 +457,7 @@ impl<'a> Channels<'a> {
         max_i_pos: ElectricCurrent,
     ) -> (ElectricCurrent, ElectricCurrent) {
         let max = ElectricCurrent::new::<ampere>(3.0);
-        let duty = (max_i_pos / max).get::<ratio>();
+        let duty = (max_i_pos.min(MAX_I).max(ElectricCurrent::zero()) / max).get::<ratio>();
         let duty = self.set_pwm(channel, PwmPin::MaxIPos, duty);
         (duty * max, max)
     }
@@ -429,13 +468,17 @@ impl<'a> Channels<'a> {
         max_i_neg: ElectricCurrent,
     ) -> (ElectricCurrent, ElectricCurrent) {
         let max = ElectricCurrent::new::<ampere>(3.0);
-        let duty = (max_i_neg / max).get::<ratio>();
+        let duty = (max_i_neg.min(MAX_I).max(ElectricCurrent::zero()) / max).get::<ratio>();
         let duty = self.set_pwm(channel, PwmPin::MaxINeg, duty);
         (duty * max, max)
     }
 
     fn report(&mut self, channel: usize) -> Report {
+        let i_set = self.get_i_set(channel);
+        let i_measured = self.get_i_measured(channel);
+        let v_measured = self.get_v_measured(channel);
         let state = self.channel_state(channel);
+        let pid_output = ElectricCurrent::new::<ampere>(state.pid.y1);
         Report {
             channel,
             time: state.get_adc_time(),
@@ -445,14 +488,10 @@ impl<'a> Channels<'a> {
                 .get_temperature()
                 .map(|temperature| temperature.get::<degree_celsius>()),
             pid_engaged: state.pid_engaged,
-            pid_output: ElectricCurrent::new::<ampere>(state.pid.y1),
-            i_set: self.get_i_set(channel),
-            i_measured: if self.hwrev.major > 2 {
-                Some(self.get_i_measured(channel))
-            } else {
-                None
-            },
-            v_measured: self.get_v_measured(channel),
+            pid_output,
+            i_set,
+            i_measured,
+            v_measured,
         }
     }
 
@@ -485,8 +524,8 @@ impl<'a> Channels<'a> {
         PwmSummary {
             channel,
             center: CenterPointJson(self.channel_state(channel).center.clone()),
-            i_set: (self.get_i_set(channel), ElectricCurrent::new::<ampere>(3.0)).into(),
-            max_v: (self.get_max_v(channel), ElectricPotential::new::<volt>(5.0)).into(),
+            i_set: (self.get_i_set(channel), MAX_I).into(),
+            max_v: self.get_max_v(channel).into(),
             max_i_pos: self.get_max_i_pos(channel).into(),
             max_i_neg: self.get_max_i_neg(channel).into(),
         }
@@ -533,11 +572,9 @@ impl<'a> Channels<'a> {
     }
 
     pub fn max_abs_i_measured(&mut self) -> ElectricCurrent {
-        max_by(
-            self.get_i_measured(0).abs(),
-            self.get_i_measured(1).abs(),
-            |a, b| a.partial_cmp(b).unwrap_or(core::cmp::Ordering::Equal),
-        )
+        max_by(self.get_i_measured(0).abs(), self.get_i_measured(1).abs(), |a, b| {
+            a.partial_cmp(b).unwrap_or(core::cmp::Ordering::Equal)
+        })
     }
 }
 
@@ -551,7 +588,7 @@ pub struct Report {
     pid_engaged: bool,
     pid_output: ElectricCurrent,
     i_set: ElectricCurrent,
-    i_measured: Option<ElectricCurrent>,
+    i_measured: ElectricCurrent,
     v_measured: ElectricPotential,
 }
 

src/command_handler.rs

@@ -35,9 +35,9 @@ pub enum Handler {
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum Error {
-    Report,
-    PostFilterRate,
-    Flash,
+    ReportError,
+    PostFilterRateError,
+    FlashError,
 }
 
 pub type JsonBuffer = Vec<u8, U1024>;
@@ -87,7 +87,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize report: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                return Err(Error::Report);
+                return Err(Error::ReportError);
             }
         }
         Ok(Handler::Handled)
@@ -101,7 +101,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize pid summary: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                return Err(Error::Report);
+                return Err(Error::ReportError);
             }
         }
         Ok(Handler::Handled)
@@ -115,7 +115,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize pwm summary: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                return Err(Error::Report);
+                return Err(Error::ReportError);
             }
         }
         Ok(Handler::Handled)
@@ -132,7 +132,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize steinhart-hart summaries: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                return Err(Error::Report);
+                return Err(Error::ReportError);
             }
         }
         Ok(Handler::Handled)
@@ -146,7 +146,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize postfilter summary: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                return Err(Error::Report);
+                return Err(Error::ReportError);
             }
         }
         Ok(Handler::Handled)
@@ -207,11 +207,11 @@ impl Handler {
         channel: usize,
         center: CenterPoint,
     ) -> Result<Handler, Error> {
-        let i_tec = channels.get_i_set(channel);
+        let i_set = channels.get_i_set(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)
@@ -287,7 +287,7 @@ impl Handler {
                     socket,
                     b"{{\"error\": \"unable to choose postfilter rate\"}}",
                 );
-                return Err(Error::PostFilterRate);
+                return Err(Error::PostFilterRateError);
             }
         }
         Ok(Handler::Handled)
@@ -313,7 +313,7 @@ impl Handler {
                     Err(e) => {
                         error!("unable to load config from flash: {:?}", e);
                         let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                        return Err(Error::Flash);
+                        return Err(Error::FlashError);
                     }
                 }
             }
@@ -338,7 +338,7 @@ impl Handler {
                     Err(e) => {
                         error!("unable to save channel {} config to flash: {:?}", c, e);
                         let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                        return Err(Error::Flash);
+                        return Err(Error::FlashError);
                     }
                 }
             }
@@ -409,7 +409,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize fan summary: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                Err(Error::Report)
+                Err(Error::ReportError)
             }
         }
     }
@@ -458,7 +458,7 @@ impl Handler {
             Err(e) => {
                 error!("unable to serialize HWRev summary: {:?}", e);
                 let _ = writeln!(socket, "{{\"error\":\"{:?}\"}}", e);
-                Err(Error::Report)
+                Err(Error::ReportError)
             }
         }
     }

src/config.rs

@@ -1,6 +1,7 @@
 use crate::{
     ad7172::PostFilter, channels::Channels, command_parser::CenterPoint, pid, steinhart_hart,
 };
+use num_traits::Zero;
 use serde::{Deserialize, Serialize};
 use uom::si::{
     electric_current::ampere,
@@ -14,6 +15,7 @@ pub struct ChannelConfig {
     pid: pid::Parameters,
     pid_target: f32,
     pid_engaged: bool,
+    i_set: ElectricCurrent,
     sh: steinhart_hart::Parameters,
     pwm: PwmLimits,
     /// uses variant `PostFilter::Invalid` instead of `None` to save space
@@ -31,11 +33,17 @@ 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,
+            i_set,
             sh: state.sh.clone(),
             pwm,
             adc_postfilter,
@@ -57,6 +65,7 @@ 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);
     }
 }
 
@@ -69,7 +78,7 @@ struct PwmLimits {
 
 impl PwmLimits {
     pub fn new(channels: &mut Channels, channel: usize) -> Self {
-        let max_v = channels.get_max_v(channel);
+        let (max_v, _) = channels.get_max_v(channel);
         let (max_i_pos, _) = channels.get_max_i_pos(channel);
         let (max_i_neg, _) = channels.get_max_i_neg(channel);
         PwmLimits {

src/fan_ctrl.rs

@@ -1,4 +1,4 @@
-use crate::{command_handler::JsonBuffer, hw_rev::HWSettings};
+use crate::{channels::MAX_I, command_handler::JsonBuffer, hw_rev::HWSettings};
 use num_traits::Float;
 use serde::Serialize;
 use stm32f4xx_hal::{
@@ -9,9 +9,6 @@ use uom::si::{electric_current::ampere, f64::ElectricCurrent};
 
 pub type FanPin = PwmChannels<TIM8, pwm::C4>;
 
-// as stated in the schematics
-const MAX_I: f32 = 3.0;
-
 const MAX_USER_FAN_PWM: f32 = 100.0;
 const MIN_USER_FAN_PWM: f32 = 1.0;
 
@@ -49,7 +46,7 @@ impl FanCtrl {
     pub fn cycle(&mut self, max_abs_i_measured: ElectricCurrent) {
         self.max_abs_i_measured = max_abs_i_measured.get::<ampere>() as f32;
         if self.fan_auto && self.hw_settings.fan_available {
-            let scaled_current = self.max_abs_i_measured / MAX_I;
+            let scaled_current = self.max_abs_i_measured / MAX_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))
@@ -62,7 +59,7 @@ impl FanCtrl {
         if self.hw_settings.fan_available {
             let summary = FanSummary {
                 fan_pwm: self.get_pwm(),
-                max_abs_i_measured: self.max_abs_i_measured,
+                abs_max_tec_i: self.max_abs_i_measured,
                 auto_mode: self.fan_auto,
                 k_a: self.k_a,
                 k_b: self.k_b,
@@ -98,7 +95,9 @@ impl FanCtrl {
             return 0f32;
         }
         let fan = self.fan.as_mut().unwrap();
-        let fan_pwm = fan_pwm.clamp(MIN_USER_FAN_PWM as u32, MAX_USER_FAN_PWM as u32);
+        let fan_pwm = fan_pwm
+            .min(MAX_USER_FAN_PWM as u32)
+            .max(MIN_USER_FAN_PWM as u32);
         let duty = scale_number(
             fan_pwm as f32,
             self.hw_settings.min_fan_pwm,
@@ -157,7 +156,7 @@ fn scale_number(unscaled: f32, to_min: f32, to_max: f32, from_min: f32, from_max
 #[derive(Serialize)]
 pub struct FanSummary {
     fan_pwm: u32,
-    max_abs_i_measured: f32,
+    abs_max_tec_i: f32,
     auto_mode: bool,
     k_a: f32,
     k_b: f32,

src/main.rs

@@ -147,7 +147,7 @@ fn main() -> ! {
 
     let mut store = flash_store::store(dp.FLASH);
 
-    let mut channels = Channels::new(pins, &hwrev);
+    let mut channels = Channels::new(pins);
     for c in 0..CHANNELS {
         match store.read_value::<ChannelConfig>(CHANNEL_CONFIG_KEY[c]) {
             Ok(Some(config)) => config.apply(&mut channels, c),
@@ -280,10 +280,10 @@ fn main() -> ! {
                     }
 
                     // Apply new IPv4 address/gateway
-                    if let Some(config) = new_ipv4_config.take() {
+                    new_ipv4_config.take().map(|config| {
                         server.set_ipv4_config(config.clone());
                         ipv4_config = config;
-                    }
+                    });
 
                     // Update watchdog
                     wd.feed();

src/pid.rs

@@ -54,14 +54,12 @@ 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)
-            + f64::from(self.parameters.kp) * (self.target - self.u1);
+            + self.x2 * f64::from(self.parameters.kd);
         if output < self.parameters.output_min.into() {
             output = self.parameters.output_min.into();
         }

src/pins.rs

@@ -58,21 +58,31 @@ pub trait ChannelPins {
     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 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 DacFeedbackPin = PA5<Analog>;
     type TecUMeasPin = PC3<Analog>;
@@ -168,10 +178,22 @@ impl Pins {
             clocks, tim1, tim3, gpioc.pc6, gpioc.pc7, gpioe.pe9, gpioe.pe11, 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();
         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();
@@ -188,7 +210,11 @@ impl Pins {
         let (dac1_spi, dac1_sync) = Self::setup_dac1(clocks, spi5, gpiof.pf7, gpiof.pf6, gpiof.pf9);
         let mut shdn1 = gpioe.pe15.into_push_pull_output();
         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();
@@ -211,14 +237,6 @@ 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(),

src/server.rs

@@ -103,11 +103,16 @@ impl<'a, 'b, S: Default> Server<'a, 'b, S> {
     fn set_ipv4_address(&mut self, ipv4_address: Ipv4Cidr) {
         self.net.update_ip_addrs(|addrs| {
             for addr in addrs.iter_mut() {
-                if let IpCidr::Ipv4(_) = addr {
+                match addr {
+                    IpCidr::Ipv4(_) => {
                         *addr = IpCidr::Ipv4(ipv4_address);
                         // done
                         break;
                     }
+                    _ => {
+                        // skip
+                    }
+                }
             }
         });
     }

src/session.rs

@@ -111,13 +111,19 @@ impl Session {
         for (i, b) in buf.iter().enumerate() {
             buf_bytes = i + 1;
             let line = self.reader.feed(*b);
-            if let Some(line) = line {
+            match line {
+                Some(line) => {
                     let command = Command::parse(line);
-                if let Ok(Command::Reporting(reporting)) = command {
+                    match command {
+                        Ok(Command::Reporting(reporting)) => {
                             self.reporting = reporting;
                         }
+                        _ => {}
+                    }
                     return (buf_bytes, command.into());
                 }
+                None => {}
+            }
         }
         (buf_bytes, SessionInput::Nothing)
     }