README: Document swap status in report

Signed-off-by: Egor Savkin <es@m-labs.hk>

README.md

@@ -84,7 +84,9 @@ invalidate the first line of input.
 
 ### Reading ADC input
 
-ADC input data is provided in reports. Query for the latest report with the command `report`. See the *Reports* section below.
+Set report mode to `on` for a continuous stream of input data.
+
+The scope of this setting is per TCP session.
 
 
 ### TCP commands
@@ -102,7 +104,7 @@ formatted as line-delimited JSON.
 | `pwm <0/1> max_i_neg <amp>`               | Set maximum negative output current                                           |
 | `pwm <0/1> max_v <volt>`                  | Set maximum output voltage                                                    |
 | `pwm <0/1> i_set <amp>`                   | Disengage PID, set fixed output current                                       |
-| `pwm <0/1> polarity <normal/reversed>`     | Set output current polarity, with 'normal' being the front panel polarity     |
+| `pwm <0/1> polarity_swapped <false/true>` | Swap output current polarity on channel                                       |
 | `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> vref`                       | Set the MAX1968 0A-centerpoint to measure from VREF                           |
@@ -185,8 +187,6 @@ 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
@@ -252,7 +252,8 @@ pwm 0 pid
 
 ## Reports
 
-Use the bare `report` command to obtain a single report. Reports are JSON objects
+Use the bare `report` command to obtain a single report. Enable
+continuous reporting with `report mode on`. Reports are JSON objects
 with the following keys.
 
 | Key               | Unit            | Description                                                        |
@@ -263,6 +264,7 @@ with the following keys.
 | `sens`            | Ohms            | Thermistor resistance derived from `adc`                           |
 | `temperature`     | Degrees Celsius | Steinhart-Hart conversion result derived from `sens`               |
 | `pid_engaged`     | Boolean         | `true` if in closed-loop mode                                      |
+| `current_swapped` | Boolean         | `true` if TEC current direction is swapped relative to front panel |
 | `i_set`           | Amperes         | TEC output current                                                 |
 | `dac_value`       | Volts           | AD5680 output derived from `i_set`                                 |
 | `dac_feedback`    | Volts           | ADC measurement of the AD5680 output                               |

pytec/pytec/client.py

@@ -1,7 +1,6 @@
 import socket
 import json
 import logging
-import time
 
 class CommandError(Exception):
     pass
@@ -57,14 +56,12 @@ class Client:
               'max_i_neg': {'max': 3.0, 'value': 3.0},
               'max_v': {'max': 5.988, 'value': 5.988},
               'max_i_pos': {'max': 3.0, 'value': 3.0}},
-              'polarity': 'normal',
              {'channel': 1,
               'center': 'vref',
               'i_set': {'max': 2.9802790335151985, 'value': -0.02002179650216762},
               'max_i_neg': {'max': 3.0, 'value': 3.0},
               'max_v': {'max': 5.988, 'value': 5.988},
               'max_i_pos': {'max': 3.0, 'value': 3.0}}
-              'polarity': 'normal',
             ]
         """
         return self._get_conf("pwm")
@@ -129,8 +126,9 @@ 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
@@ -138,7 +136,6 @@ 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

src/channel_state.rs

@@ -17,7 +17,7 @@ use crate::{
     ad7172,
     pid,
     steinhart_hart as sh,
-    command_parser::{CenterPoint, Polarity},
+    command_parser::CenterPoint,
 };
 
 const R_INNER: f64 = 2.0 * 5100.0;
@@ -35,7 +35,7 @@ pub struct ChannelState {
     pub pid_engaged: bool,
     pub pid: pid::Controller,
     pub sh: sh::Parameters,
-    pub polarity: Polarity,
+    pub polarity_swapped: bool,
 }
 
 impl ChannelState {
@@ -52,7 +52,7 @@ impl ChannelState {
             pid_engaged: false,
             pid: pid::Controller::new(pid::Parameters::default()),
             sh: sh::Parameters::default(),
-            polarity: Polarity::Normal,
+            polarity_swapped: false,
         }
     }
 

src/channels.rs

@@ -17,7 +17,7 @@ use crate::{
     ad7172,
     channel::{Channel, Channel0, Channel1},
     channel_state::ChannelState,
-    command_parser::{CenterPoint, PwmPin, Polarity},
+    command_parser::{CenterPoint, PwmPin},
     command_handler::JsonBuffer,
     pins::{self, Channel0VRef, Channel1VRef},
     steinhart_hart,
@@ -45,11 +45,7 @@ pub const MAX_TEC_V: ElectricPotential = ElectricPotential {
     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,
@@ -159,9 +155,10 @@ impl Channels {
     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 {
+        let negate = if self.channel_state(channel).polarity_swapped {
-            Polarity::Normal => 1.0,
+            -1.0
-            Polarity::Reversed => -1.0,
+        } else {
+            1.0
         };
         let vref_meas = match channel.into() {
             0 => self.channel0.vref_meas,
@@ -305,6 +302,7 @@ impl Channels {
         let mut best_error = ElectricPotential::new::<volt>(100.0);
 
         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 => {
@@ -323,7 +321,7 @@ impl Channels {
                     break;
                 } else if error < best_error {
                     best_error = error;
-                    start_value = value;
+                    start_value = prev_value;
 
                     let vref = (value as f64 / ad5680::MAX_VALUE as f64) * DAC_OUT_V_MAX;
                     match channel {
@@ -332,6 +330,8 @@ impl Channels {
                         _ => unreachable!(),
                     }
                 }
+
+                prev_value = value;
             }
         }
 
@@ -390,27 +390,32 @@ impl Channels {
     }
 
     pub fn get_max_i_pos(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
-        let duty = match self.channel_state(channel).polarity {
+        let max = ElectricCurrent::new::<ampere>(3.0);
-            Polarity::Normal => self.get_pwm(channel, PwmPin::MaxIPos),
+        let duty = if self.channel_state(channel).polarity_swapped {
-            Polarity::Reversed => self.get_pwm(channel, PwmPin::MaxINeg),
+            self.get_pwm(channel, PwmPin::MaxINeg)
+        } else {
+            self.get_pwm(channel, PwmPin::MaxIPos)
         };
-        (duty * MAX_TEC_I_DUTY_TO_CURRENT_RATE, MAX_TEC_I)
+        (duty * max, MAX_TEC_I)
     }
 
     pub fn get_max_i_neg(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
-        let duty = match self.channel_state(channel).polarity {
+        let max = ElectricCurrent::new::<ampere>(3.0);
-            Polarity::Normal => self.get_pwm(channel, PwmPin::MaxINeg),
+        let duty = if self.channel_state(channel).polarity_swapped {
-            Polarity::Reversed => self.get_pwm(channel, PwmPin::MaxIPos),
+            self.get_pwm(channel, PwmPin::MaxIPos)
+        } else {
+            self.get_pwm(channel, PwmPin::MaxINeg)
         };
-        (duty * MAX_TEC_I_DUTY_TO_CURRENT_RATE, MAX_TEC_I)
+        (duty * max, MAX_TEC_I)
     }
 
     // Get current passing through TEC
     pub fn get_tec_i(&mut self, channel: usize) -> ElectricCurrent {
         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 {
+        if self.channel_state(channel).polarity_swapped {
-            Polarity::Normal => tec_i,
+            -tec_i
-            Polarity::Reversed => -tec_i,
+        } else {
+            tec_i
         }
     }
 
@@ -455,31 +460,33 @@ impl Channels {
 
     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.min(MAX_TEC_I).max(ElectricCurrent::zero()) / MAX_TEC_I_DUTY_TO_CURRENT_RATE).get::<ratio>();
+        let duty = (max_i_pos.min(MAX_TEC_I).max(ElectricCurrent::zero()) / max).get::<ratio>();
-        let duty = match self.channel_state(channel).polarity {
+        let duty = if self.channel_state(channel).polarity_swapped {
-            Polarity::Normal => self.set_pwm(channel, PwmPin::MaxIPos, duty),
+            self.set_pwm(channel, PwmPin::MaxINeg, duty)
-            Polarity::Reversed => self.set_pwm(channel, PwmPin::MaxINeg, duty),
+        } else {
+            self.set_pwm(channel, PwmPin::MaxIPos, duty)
         };
-        (duty * MAX_TEC_I_DUTY_TO_CURRENT_RATE, max)
+        (duty * max, 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.min(MAX_TEC_I).max(ElectricCurrent::zero()) / MAX_TEC_I_DUTY_TO_CURRENT_RATE).get::<ratio>();
+        let duty = (max_i_neg.min(MAX_TEC_I).max(ElectricCurrent::zero()) / max).get::<ratio>();
-        let duty = match self.channel_state(channel).polarity {
+        let duty = if self.channel_state(channel).polarity_swapped {
-            Polarity::Normal => self.set_pwm(channel, PwmPin::MaxINeg, duty),
+            self.set_pwm(channel, PwmPin::MaxIPos, duty)
-            Polarity::Reversed => self.set_pwm(channel, PwmPin::MaxIPos, duty),
+        } else {
+            self.set_pwm(channel, PwmPin::MaxINeg, duty)
         };
-        (duty * MAX_TEC_I_DUTY_TO_CURRENT_RATE, max)
+        (duty * max, max)
     }
 
-    pub fn set_polarity(&mut self, channel: usize, polarity: Polarity) {
+    pub fn swap_polarity(&mut self, channel: usize, swapped: bool) {
-        if self.channel_state(channel).polarity != polarity {
+        if self.channel_state(channel).polarity_swapped != swapped {
             let i_set = self.channel_state(channel).i_set;
             let max_i_pos = self.get_max_i_pos(channel).0;
             let max_i_neg = self.get_max_i_neg(channel).0;
-            self.channel_state(channel).polarity = polarity;
 
+            self.channel_state(channel).polarity_swapped = swapped;
             self.set_i(channel, i_set);
             self.set_max_i_pos(channel, max_i_pos);
             self.set_max_i_neg(channel, max_i_neg);
@@ -502,6 +509,7 @@ impl Channels {
             temperature: state.get_temperature()
                 .map(|temperature| temperature.get::<degree_celsius>()),
             pid_engaged: state.pid_engaged,
+            current_swapped: state.polarity_swapped,
             i_set,
             dac_value,
             dac_feedback: self.adc_read(channel, PinsAdcReadTarget::DacVfb, 1),
@@ -545,7 +553,6 @@ impl Channels {
             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(),
-            polarity: PolarityJson(self.channel_state(channel).polarity.clone()),
         }
     }
 
@@ -601,6 +608,7 @@ pub struct Report {
     sens: Option<ElectricalResistance>,
     temperature: Option<f64>,
     pid_engaged: bool,
+    current_swapped: bool,
     i_set: ElectricCurrent,
     dac_value: ElectricPotential,
     dac_feedback: ElectricPotential,
@@ -627,21 +635,6 @@ impl Serialize for CenterPointJson {
     }
 }
 
-pub struct PolarityJson(Polarity);
-
-// used in JSON encoding, not for config
-impl Serialize for PolarityJson {
-    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",
-        })
-    }
-}
-
 #[derive(Serialize)]
 pub struct PwmSummaryField<T: Serialize> {
     value: T,
@@ -662,7 +655,6 @@ pub struct PwmSummary {
     max_v: PwmSummaryField<ElectricPotential>,
     max_i_pos: PwmSummaryField<ElectricCurrent>,
     max_i_neg: PwmSummaryField<ElectricCurrent>,
-    polarity: PolarityJson,
 }
 
 #[derive(Serialize)]

src/command_handler.rs

@@ -11,8 +11,7 @@ use super::{
         CenterPoint, 
         PidParameter, 
         PwmPin, 
-        ShParameter,
+        ShParameter
-        Polarity
     },
     ad7172,
     CHANNEL_CONFIG_KEY,
@@ -23,6 +22,7 @@ use super::{
     config::ChannelConfig,
     dfu,
     flash_store::FlashStore,
+    session::Session,
     FanCtrl,
     hw_rev::HWRev,
 };
@@ -87,6 +87,16 @@ 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) => {
@@ -171,8 +181,8 @@ impl Handler {
         Ok(Handler::Handled)
     }
 
-    fn set_polarity(socket: &mut TcpSocket, channels: &mut Channels, channel: usize, polarity: Polarity) -> Result<Handler, Error> {
+    fn swap_polarity (socket: &mut TcpSocket, channels: &mut Channels, channel: usize, swapped: bool) -> Result<Handler, Error> {
-        channels.set_polarity(channel, polarity);
+        channels.swap_polarity(channel, swapped);
         send_line(socket, b"{}");
         Ok(Handler::Handled)
     }
@@ -408,9 +418,11 @@ impl Handler {
         }
     }
 
-    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> {
+    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> {
         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),
@@ -418,7 +430,7 @@ impl Handler {
             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::PwmPolaritySwapped { channel, swapped } => Handler::swap_polarity(socket, channels, channel, swapped),
             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),

src/command_parser.rs

@@ -96,6 +96,7 @@ pub struct Ipv4Config {
 #[derive(Debug, Clone, PartialEq)]
 pub enum ShowCommand {
     Input,
+    Reporting,
     Pwm,
     Pid,
     SteinhartHart,
@@ -135,12 +136,6 @@ pub enum CenterPoint {
     Override(f32),
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
-pub enum Polarity {
-    Normal,
-    Reversed,
-}
-
 #[derive(Debug, Clone, PartialEq)]
 pub enum Command {
     Quit,
@@ -153,6 +148,7 @@ pub enum Command {
     Reset,
     Ipv4(Ipv4Config),
     Show(ShowCommand),
+    Reporting(bool),
     /// PWM parameter setting
     Pwm {
         channel: usize,
@@ -163,9 +159,9 @@ pub enum Command {
     PwmPid {
         channel: usize,
     },
-    PwmPolarity {
+    PwmPolaritySwapped {
         channel: usize,
-        polarity: Polarity,
+        swapped: bool,
     },
     CenterPoint {
         channel: usize,
@@ -241,6 +237,18 @@ 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 boolean(input: &[u8]) -> IResult<&[u8], bool> {
+    alt((value(false, tag("false")),
+         value(true, tag("true"))
+    ))(input)
+}
+
 fn channel(input: &[u8]) -> IResult<&[u8], usize> {
     map(one_of("01"), |c| (c as usize) - ('0' as usize))(input)
 }
@@ -248,8 +256,24 @@ fn channel(input: &[u8]) -> IResult<&[u8], usize> {
 fn report(input: &[u8]) -> IResult<&[u8], Command> {
     preceded(
         tag("report"),
+        alt((
+            preceded(
+                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)
 }
 
@@ -307,14 +331,12 @@ fn pwm_pid(input: &[u8]) -> IResult<&[u8], ()> {
     value((), tag("pid"))(input)
 }
 
-fn pwm_polarity(input: &[u8]) -> IResult<&[u8], Polarity> {
+fn pwm_polarity_swapped(input: &[u8]) -> IResult<&[u8], bool> {
     preceded(
-        tag("polarity"),
+        tag("polarity_swapped"),
         preceded(
             whitespace,
-            alt((value(Polarity::Normal, tag("normal")),
+            boolean,
-                 value(Polarity::Reversed, tag("reversed"))
-            ))
         )
     )(input)
 }
@@ -332,8 +354,8 @@ fn pwm(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
                     Ok((input, Ok(Command::PwmPid { channel })))
                 },
                 |input| {
-                    let (input, polarity) = pwm_polarity(input)?;
+                    let (input, swapped) = pwm_polarity_swapped(input)?;
-                    Ok((input, Ok(Command::PwmPolarity { channel, polarity })))
+                    Ok((input, Ok(Command::PwmPolaritySwapped { channel, swapped })))
                 },
                 |input| {
                     let (input, config) = pwm_setup(input)?;
@@ -684,6 +706,24 @@ 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");

src/config.rs

@@ -8,7 +8,7 @@ use uom::si::{
 use crate::{
     ad7172::PostFilter,
     channels::Channels,
-    command_parser::{CenterPoint, Polarity},
+    command_parser::CenterPoint,
     pid,
     steinhart_hart,
 };
@@ -20,7 +20,7 @@ pub struct ChannelConfig {
     pid_target: f32,
     pid_engaged: bool,
     i_set: ElectricCurrent,
-    polarity: Polarity,
+    polarity_swapped: bool,
     sh: steinhart_hart::Parameters,
     pwm: PwmLimits,
     /// uses variant `PostFilter::Invalid` instead of `None` to save space
@@ -47,7 +47,7 @@ impl ChannelConfig {
             pid_target: state.pid.target as f32,
             pid_engaged: state.pid_engaged,
             i_set,
-            polarity: state.polarity.clone(),
+            polarity_swapped: state.polarity_swapped,
             sh: state.sh.clone(),
             pwm,
             adc_postfilter,
@@ -70,7 +70,7 @@ impl ChannelConfig {
         };
         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());
+        channels.swap_polarity(channel, self.polarity_swapped);
     }
 }
 

src/main.rs

@@ -58,7 +58,7 @@ mod hw_rev;
 
 const HSE: MegaHertz = MegaHertz(8);
 #[cfg(not(feature = "semihosting"))]
-const WATCHDOG_INTERVAL: u32 = 1_000;
+const WATCHDOG_INTERVAL: u32 = 2_000;
 #[cfg(feature = "semihosting")]
 const WATCHDOG_INTERVAL: u32 = 30_000;
 
@@ -180,7 +180,10 @@ fn main() -> ! {
             loop {
                 let mut new_ipv4_config = None;
                 let instant = Instant::from_millis(i64::from(timer::now()));
-                channels.poll_adc(instant);
+                let updated_channel = 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());
 
@@ -213,7 +216,7 @@ 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, &mut store, &mut ipv4_config, &mut fan_ctrl, hwrev) {
+                                    match Handler::handle_command(command, &mut socket, &mut channels, session, &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(),
@@ -228,6 +231,19 @@ 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/session.rs

@@ -1,4 +1,5 @@
 use super::command_parser::{Command, Error as ParserError};
+use super::channels::CHANNELS;
 
 const MAX_LINE_LEN: usize = 64;
 
@@ -52,6 +53,8 @@ impl From<Result<Command, ParserError>> for SessionInput {
 
 pub struct Session {
     reader: LineReader,
+    reporting: bool,
+    report_pending: [bool; CHANNELS],
 }
 
 impl Default for Session {
@@ -64,11 +67,43 @@ 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) {
@@ -79,6 +114,12 @@ 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 => {}