Add swap command

Per-channel current swapping, for use with Zotino in the meantime on
HWRevs < 3.0 as the Zotino headers are swapped on the Thermostat.

README.md

@@ -130,6 +130,7 @@ formatted as line-delimited JSON.
 | `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) |
 | `hwrev`                          | Show hardware revision, and settings related to it                            |
+| `swap [0/1]`                     | Swap TEC polarities for channel all/0/1 (For use with Zotino)                 |
 
 
 ## USB
@@ -180,9 +181,11 @@ postfilter rate can be tuned with the `postfilter` command.
 
 ## Thermo-Electric Cooling (TEC)
 
-- Connect TEC module device 0 to TEC0- and TEC0+.
+- Connect TEC module device 0 to TEC0-/T0- and TEC0+/T0+.
-- Connect TEC module device 1 to TEC1- and TEC1+.
+- Connect TEC module device 1 to TEC1-/T1- and TEC1+/T1+.
-- The GND pin is for shielding not for sinking TEC module currents.
+- The GND pin is for shielding, not for sinking TEC module currents.
+
+For Zotino temperature regulation, connect an IDC cable to the internal Zotino header labeled TEC1/TEC2. For pre 3.0 Thermostats, use the `swap` command for those channels.
 
 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.
 

src/channel_state.rs

@@ -35,6 +35,7 @@ pub struct ChannelState {
     pub pid_engaged: bool,
     pub pid: pid::Controller,
     pub sh: sh::Parameters,
+    pub swap_tec_polarity: bool,
 }
 
 impl ChannelState {
@@ -51,6 +52,7 @@ impl ChannelState {
             pid_engaged: false,
             pid: pid::Controller::new(pid::Parameters::default()),
             sh: sh::Parameters::default(),
+            swap_tec_polarity: false,
         }
     }
 

src/channels.rs

@@ -118,7 +118,11 @@ impl<'a> Channels<'a> {
 
     pub fn get_i(&mut self, channel: usize) -> ElectricCurrent {
         let i_set = self.channel_state(channel).i_set;
-        i_set
+        if self.channel_state(channel).swap_tec_polarity {
+            -i_set
+        } else {
+            i_set
+        }
     }
 
     /// i_set DAC
@@ -137,13 +141,16 @@ impl<'a> Channels<'a> {
         // Silently clamp i_set
         let i_ceiling = ElectricCurrent::new::<ampere>(MAX_TEC_I);
         let i_floor = ElectricCurrent::new::<ampere>(-MAX_TEC_I);
-        let i_set = i_set.min(i_ceiling).max(i_floor);
+        let mut i_set = i_set.min(i_ceiling).max(i_floor);
 
         let vref_meas = match channel.into() {
             0 => self.channel0.vref_meas,
             1 => self.channel1.vref_meas,
             _ => unreachable!(),
         };
+        if self.channel_state(channel).swap_tec_polarity {
+            i_set = -i_set;
+        }
         let center_point = vref_meas;
         let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
         let voltage = i_set * 10.0 * r_sense + center_point;
@@ -390,7 +397,12 @@ impl<'a> Channels<'a> {
 
     // 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.read_itec(channel) - self.read_vref(channel)) / ElectricalResistance::new::<ohm>(0.4);
+        if self.channel_state(channel).swap_tec_polarity {
+            -tec_i
+        } else {
+            tec_i
+        }
     }
 
     // Get voltage across TEC

src/command_handler.rs

@@ -412,6 +412,16 @@ impl Handler {
         }
     }
 
+    fn swap_tec_polarity (socket: &mut TcpSocket, channels: &mut Channels, channel: Option<usize>) -> Result<Handler, Error> {
+        for c in 0..CHANNELS {
+            if channel.is_none() || channel == Some(c) {
+                channels.channel_state(c).swap_tec_polarity = !channels.channel_state(c).swap_tec_polarity;
+            }
+        }
+        send_line(socket, b"{}");
+        Ok(Handler::Handled)
+    }
+
     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),
@@ -441,6 +451,7 @@ impl Handler {
             Command::FanCurve { k_a, k_b, k_c } => Handler::fan_curve(socket, fan_ctrl, k_a, k_b, k_c),
             Command::FanCurveDefaults => Handler::fan_defaults(socket, fan_ctrl),
             Command::ShowHWRev => Handler::show_hwrev(socket, hwrev),
+            Command::SwapTECPolarity { channel } => Handler::swap_tec_polarity(socket, channels, channel),
         }
     }
 }

src/command_parser.rs

@@ -191,6 +191,9 @@ pub enum Command {
     },
     FanCurveDefaults,
     ShowHWRev,
+    SwapTECPolarity {
+        channel: Option<usize>,
+    },
 }
 
 fn end(input: &[u8]) -> IResult<&[u8], ()> {
@@ -584,6 +587,22 @@ fn fan_curve(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
     ))(input)
 }
 
+fn swap(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
+    let (input, _) = tag("swap")(input)?;
+    let (input, channel) = alt((
+        |input| {
+            let (input, _) = whitespace(input)?;
+            let (input, channel) = channel(input)?;
+            let (input, _) = end(input)?;
+            Ok((input, Some(channel)))
+        },
+        value(None, end)
+    ))(input)?;
+
+    let result = Ok(Command::SwapTECPolarity { channel });
+    Ok((input, result))
+}
+
 fn command(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
     alt((value(Ok(Command::Quit), tag("quit")),
          load,
@@ -600,6 +619,7 @@ fn command(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
          fan,
          fan_curve,
          value(Ok(Command::ShowHWRev), tag("hwrev")),
+         swap,
     ))(input)
 }
 

src/config.rs

@@ -22,6 +22,7 @@ pub struct ChannelConfig {
     pwm: PwmLimits,
     /// uses variant `PostFilter::Invalid` instead of `None` to save space
     adc_postfilter: PostFilter,
+    swap_tec_polarity: bool,
 }
 
 impl ChannelConfig {
@@ -41,6 +42,7 @@ impl ChannelConfig {
             sh: state.sh.clone(),
             pwm,
             adc_postfilter,
+            swap_tec_polarity: state.swap_tec_polarity,
         }
     }
 
@@ -51,6 +53,7 @@ impl ChannelConfig {
         state.pid.target = self.pid_target.into();
         state.pid_engaged = self.pid_engaged;
         state.sh = self.sh.clone();
+        state.swap_tec_polarity = self.swap_tec_polarity;
 
         self.pwm.apply(channels, channel);