add Channels::calibrate_dac_value()

src/ad5680.rs

@@ -6,7 +6,6 @@ use stm32f4xx_hal::{
     time::MegaHertz,
     spi,
 };
-use crate::units::Volts;
 
 /// SPI Mode 1
 pub const SPI_MODE: spi::Mode = spi::Mode {
@@ -45,9 +44,7 @@ impl<SPI: Transfer<u8>, S: OutputPin> Dac<SPI, S> {
         Ok(())
     }
 
-    pub fn set(&mut self, voltage: Volts) -> Result<(), SPI::Error> {
+    pub fn set(&mut self, value: u32) -> Result<(), SPI::Error> {
-        let value = ((voltage.0 * (MAX_VALUE as f64) / 5.0) as u32)
-            .min(MAX_VALUE);
         let buf = [
             (value >> 14) as u8,
             (value >> 6) as u8,

src/channel.rs

@@ -2,7 +2,6 @@ use crate::{
     ad5680,
     channel_state::ChannelState,
     pins::{ChannelPins, ChannelPinSet},
-    units::Volts,
 };
 
 /// Marker type for the first channel
@@ -16,27 +15,35 @@ pub struct Channel<C: ChannelPins> {
     pub state: ChannelState,
     /// for `i_set`
     pub dac: ad5680::Dac<C::DacSpi, C::DacSync>,
+    /// 1 / Volts
+    pub dac_factor: f64,
     pub shdn: C::Shdn,
     /// stm32f4 integrated adc
     pub adc: C::Adc,
+    pub vref_pin: C::VRefPin,
     pub itec_pin: C::ItecPin,
     /// feedback from `dac` output
     pub dac_feedback_pin: C::DacFeedbackPin,
+    pub tec_u_meas_pin: C::TecUMeasPin,
 }
 
 impl<C: ChannelPins> Channel<C> {
     pub fn new(pins: ChannelPinSet<C>) -> Self {
         let state = ChannelState::default();
         let mut dac = ad5680::Dac::new(pins.dac_spi, pins.dac_sync);
-        let _ = dac.set(Volts(0.0));
+        let _ = dac.set(0);
+        // sensible dummy preset. calibrate_i_set() must be used.
+        let dac_factor = ad5680::MAX_VALUE as f64 / 5.0;
 
         Channel {
             state,
-            dac,
+            dac, dac_factor,
             shdn: pins.shdn,
             adc: pins.adc,
+            vref_pin: pins.vref_pin,
             itec_pin: pins.itec_pin,
             dac_feedback_pin: pins.dac_feedback_pin,
+            tec_u_meas_pin: pins.tec_u_meas_pin,
         }
     }
 }

src/channels.rs

@@ -1,6 +1,8 @@
 use stm32f4xx_hal::hal::digital::v2::OutputPin;
 use smoltcp::time::Instant;
+use log::info;
 use crate::{
+    ad5680,
     ad7172,
     channel::{Channel, Channel0, Channel1},
     channel_state::ChannelState,
@@ -10,10 +12,12 @@ use crate::{
 
 pub const CHANNELS: usize = 2;
 
+// TODO: -pub
 pub struct Channels {
     pub channel0: Channel<Channel0>,
     pub channel1: Channel<Channel1>,
     pub adc: ad7172::Adc<pins::AdcSpi, pins::AdcNss>,
+    pub tec_u_meas_adc: pins::TecUMeasAdc,
     pub pwm: pins::PwmPins,
 }
 
@@ -21,6 +25,7 @@ impl Channels {
     pub fn new(pins: pins::Pins) -> Self {
         let channel0 = Channel::new(pins.channel0);
         let channel1 = Channel::new(pins.channel1);
+        let tec_u_meas_adc = pins.tec_u_meas_adc;
         let pwm = pins.pwm;
 
         let mut adc = ad7172::Adc::new(pins.adc_spi, pins.adc_nss).unwrap();
@@ -43,7 +48,7 @@ impl Channels {
         adc.setup_channel(1, ad7172::Input::Ain2, ad7172::Input::Ain3).unwrap();
         adc.start_continuous_conversion().unwrap();
 
-        Channels { channel0, channel1, adc, pwm }
+        Channels { channel0, channel1, adc, tec_u_meas_adc, pwm }
     }
 
     pub fn channel_state<I: Into<usize>>(&mut self, channel: I) -> &mut ChannelState {
@@ -80,14 +85,21 @@ impl Channels {
 
     /// i_set DAC
     pub fn set_dac(&mut self, channel: usize, voltage: Volts) {
+        let dac_factor = match channel.into() {
+            0 => self.channel0.dac_factor,
+            1 => self.channel1.dac_factor,
+            _ => unreachable!(),
+        };
+        let value = (voltage.0 * dac_factor) as u32;
+        info!("set_dac {} {}", voltage, value);
         match channel {
             0 => {
-                self.channel0.dac.set(voltage).unwrap();
+                self.channel0.dac.set(value).unwrap();
                 self.channel0.state.dac_value = voltage;
                 self.channel0.shdn.set_high().unwrap();
             }
             1 => {
-                self.channel1.dac.set(voltage).unwrap();
+                self.channel1.dac.set(value).unwrap();
                 self.channel1.state.dac_value = voltage;
                 self.channel1.shdn.set_high().unwrap();
             }
@@ -138,4 +150,89 @@ impl Channels {
             _ => unreachable!(),
         }
     }
+
+    /// should be 1.5V
+    pub fn read_vref(&mut self, channel: usize) -> Volts {
+        match channel {
+            0 => {
+                let sample = self.channel0.adc.convert(
+                    &self.channel0.vref_pin,
+                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
+                );
+                let mv = self.channel0.adc.sample_to_millivolts(sample);
+                Volts(mv as f64 / 1000.0)
+            }
+            1 => {
+                let sample = self.channel1.adc.convert(
+                    &self.channel1.vref_pin,
+                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
+                );
+                let mv = self.channel1.adc.sample_to_millivolts(sample);
+                Volts(mv as f64 / 1000.0)
+            }
+            _ => unreachable!(),
+        }
+    }
+
+    pub fn read_tec_u_meas(&mut self, channel: usize) -> Volts {
+        match channel {
+            0 => {
+                let sample = self.tec_u_meas_adc.convert(
+                    &self.channel0.tec_u_meas_pin,
+                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
+                );
+                let mv = self.tec_u_meas_adc.sample_to_millivolts(sample);
+                Volts(mv as f64 / 1000.0)
+            }
+            1 => {
+                let sample = self.tec_u_meas_adc.convert(
+                    &self.channel1.tec_u_meas_pin,
+                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
+                );
+                let mv = self.tec_u_meas_adc.sample_to_millivolts(sample);
+                Volts(mv as f64 / 1000.0)
+            }
+            _ => unreachable!(),
+        }
+    }
+
+    /// for i_set
+    pub fn calibrate_dac_value(&mut self, channel: usize) {
+        let vref = self.read_vref(channel);
+        let mut best_value = 0;
+        let mut best_error = Volts(100.0);
+        for value in 1..=ad5680::MAX_VALUE {
+            match channel {
+                0 => {
+                    self.channel0.dac.set(value).unwrap();
+                    self.channel0.shdn.set_high().unwrap();
+                }
+                1 => {
+                    self.channel1.dac.set(value).unwrap();
+                    self.channel1.shdn.set_high().unwrap();
+                }
+                _ => unreachable!(),
+            }
+
+            let dac_feedback = self.read_dac_feedback(channel);
+            let error = vref - dac_feedback;
+            if error < Volts(0.0) {
+                info!("calibration done at {} > {}", dac_feedback, vref);
+                break;
+            } else if error < best_error {
+                best_value = value;
+                best_error = error;
+            }
+        }
+
+        self.set_dac(channel, Volts(0.0));
+        info!("best dac value for {}: {}, itec={}", vref, best_value, self.read_itec(channel));
+
+        let dac_factor = best_value as f64 / vref.0;
+        match channel {
+            0 => self.channel0.dac_factor = dac_factor,
+            1 => self.channel1.dac_factor = dac_factor,
+            _ => unreachable!(),
+        }
+    }
 }

src/main.rs

@@ -43,7 +43,7 @@ mod command_parser;
 use command_parser::{Command, ShowCommand, PwmPin};
 mod timer;
 mod units;
-use units::{Amps, Ohms, Volts};
+use units::{Ohms, Volts};
 mod pid;
 mod steinhart_hart;
 mod channels;
@@ -93,9 +93,11 @@ fn main() -> ! {
         clocks, dp.TIM1, dp.TIM3,
         dp.GPIOA, dp.GPIOB, dp.GPIOC, dp.GPIOE, dp.GPIOF, dp.GPIOG,
         dp.SPI2, dp.SPI4, dp.SPI5,
-        dp.ADC1, dp.ADC2,
+        dp.ADC1, dp.ADC2, dp.ADC3,
     );
     let mut channels = Channels::new(pins);
+    channels.calibrate_dac_value(0);
+
     timer::setup(cp.SYST, clocks);
 
     #[cfg(not(feature = "generate-hwaddr"))]
@@ -143,18 +145,21 @@ fn main() -> ! {
                                 Command::Show(ShowCommand::Input) => {
                                     for channel in 0..CHANNELS {
                                         if let Some(adc_data) = channels.channel_state(channel).adc_data {
+                                            let vref = channels.read_vref(channel);
                                             let dac_feedback = channels.read_dac_feedback(channel);
-                                            let dac_i = dac_feedback / Ohms(5.0);
 
                                             let itec = channels.read_itec(channel);
-                                            let tec_i = Amps((itec.0 - 1.5) / 8.0);
+                                            let tec_i = -(itec - Volts(1.5)) / Ohms(0.4);
+
+                                            let tec_u_meas = channels.read_tec_u_meas(channel);
 
                                             let state = channels.channel_state(channel);
                                             let _ = writeln!(
-                                                socket, "t={} raw{}=0x{:06X} dac_feedback={}/{} itec={} tec={}",
+                                                socket, "t={} adc_raw{}=0x{:06X} vref={} dac_feedback={} itec={} tec={} tec_u_meas={}",
                                                 state.adc_time, channel, adc_data,
-                                                dac_feedback, dac_i,
+                                                vref, dac_feedback,
                                                 itec, tec_i,
+                                                tec_u_meas,
                                             );
                                         }
                                     }

src/pins.rs

@@ -16,7 +16,7 @@ use stm32f4xx_hal::{
     rcc::Clocks,
     pwm::{self, PwmChannels},
     spi::{Spi, NoMiso},
-    stm32::{ADC1, ADC2, GPIOA, GPIOB, GPIOC, GPIOE, GPIOF, GPIOG, SPI2, SPI4, SPI5, TIM1, TIM3},
+    stm32::{ADC1, ADC2, ADC3, GPIOA, GPIOB, GPIOC, GPIOE, GPIOF, GPIOG, SPI2, SPI4, SPI5, TIM1, TIM3},
     time::U32Ext,
 };
 use crate::channel::{Channel0, Channel1};
@@ -27,8 +27,10 @@ pub trait ChannelPins {
     type DacSync: OutputPin;
     type Shdn: OutputPin;
     type Adc;
+    type VRefPin;
     type ItecPin;
     type DacFeedbackPin;
+    type TecUMeasPin;
 }
 
 impl ChannelPins for Channel0 {
@@ -36,8 +38,10 @@ impl ChannelPins for Channel0 {
     type DacSync = PE4<Output<PushPull>>;
     type Shdn = PE10<Output<PushPull>>;
     type Adc = Adc<ADC1>;
+    type VRefPin = PA0<Analog>;
     type ItecPin = PA6<Analog>;
     type DacFeedbackPin = PA4<Analog>;
+    type TecUMeasPin = PC2<Analog>;
 }
 
 impl ChannelPins for Channel1 {
@@ -45,8 +49,10 @@ impl ChannelPins for Channel1 {
     type DacSync = PF6<Output<PushPull>>;
     type Shdn = PE15<Output<PushPull>>;
     type Adc = Adc<ADC2>;
+    type VRefPin = PA3<Analog>;
     type ItecPin = PB0<Analog>;
     type DacFeedbackPin = PA5<Analog>;
+    type TecUMeasPin = PC3<Analog>;
 }
 
 /// SPI peripheral used for communication with the ADC
@@ -55,19 +61,23 @@ pub type AdcNss = PB12<Output<PushPull>>;
 type Dac0Spi = Spi<SPI4, (PE2<Alternate<AF5>>, NoMiso, PE6<Alternate<AF5>>)>;
 type Dac1Spi = Spi<SPI5, (PF7<Alternate<AF5>>, NoMiso, PF9<Alternate<AF5>>)>;
 
+pub type TecUMeasAdc = Adc<ADC3>;
 
 pub struct ChannelPinSet<C: ChannelPins> {
     pub dac_spi: C::DacSpi,
     pub dac_sync: C::DacSync,
     pub shdn: C::Shdn,
     pub adc: C::Adc,
+    pub vref_pin: C::VRefPin,
     pub itec_pin: C::ItecPin,
     pub dac_feedback_pin: C::DacFeedbackPin,
+    pub tec_u_meas_pin: C::TecUMeasPin,
 }
 
 pub struct Pins {
     pub adc_spi: AdcSpi,
     pub adc_nss: AdcNss,
+    pub tec_u_meas_adc: TecUMeasAdc,
     pub pwm: PwmPins,
     pub channel0: ChannelPinSet<Channel0>,
     pub channel1: ChannelPinSet<Channel1>,
@@ -80,7 +90,7 @@ impl Pins {
         tim1: TIM1, tim3: TIM3,
         gpioa: GPIOA, gpiob: GPIOB, gpioc: GPIOC, gpioe: GPIOE, gpiof: GPIOF, gpiog: GPIOG,
         spi2: SPI2, spi4: SPI4, spi5: SPI5,
-        adc1: ADC1, adc2: ADC2,
+        adc1: ADC1, adc2: ADC2, adc3: ADC3,
     ) -> Self {
         let gpioa = gpioa.split();
         let gpiob = gpiob.split();
@@ -97,6 +107,8 @@ impl Pins {
         let adc_spi = Self::setup_spi_adc(clocks, spi2, gpiob.pb10, gpiob.pb14, gpiob.pb15);
         let adc_nss = gpiob.pb12.into_push_pull_output();
 
+        let tec_u_meas_adc = Adc::adc3(adc3, true, Default::default());
+
         let pwm = PwmPins::setup(
             clocks, tim1, tim3,
             gpioc.pc6, gpioc.pc7,
@@ -112,15 +124,19 @@ impl Pins {
         let _ = shdn0.set_low();
         let mut adc0 = Adc::adc1(adc1, true, Default::default());
         adc0.enable();
+        let vref0_pin = gpioa.pa0.into_analog();
         let itec0_pin = gpioa.pa6.into_analog();
         let dac_feedback0_pin = gpioa.pa4.into_analog();
+        let tec_u_meas0_pin = gpioc.pc2.into_analog();
         let channel0 = ChannelPinSet {
             dac_spi: dac0_spi,
             dac_sync: dac0_sync,
             shdn: shdn0,
             adc: adc0,
+            vref_pin: vref0_pin,
             itec_pin: itec0_pin,
             dac_feedback_pin: dac_feedback0_pin,
+            tec_u_meas_pin: tec_u_meas0_pin,
         };
 
         let (dac1_spi, dac1_sync) = Self::setup_dac1(
@@ -131,19 +147,24 @@ impl Pins {
         let _ = shdn1.set_low();
         let mut adc1 = Adc::adc2(adc2, true, Default::default());
         adc1.enable();
+        let vref1_pin = gpioa.pa3.into_analog();
         let itec1_pin = gpiob.pb0.into_analog();
         let dac_feedback1_pin = gpioa.pa5.into_analog();
+        let tec_u_meas1_pin = gpioc.pc3.into_analog();
         let channel1 = ChannelPinSet {
             dac_spi: dac1_spi,
             dac_sync: dac1_sync,
             shdn: shdn1,
             adc: adc1,
+            vref_pin: vref1_pin,
             itec_pin: itec1_pin,
             dac_feedback_pin: dac_feedback1_pin,
+            tec_u_meas_pin: tec_u_meas1_pin,
         };
 
         Pins {
             adc_spi, adc_nss,
+            tec_u_meas_adc,
             pwm,
             channel0,
             channel1,

src/units.rs

@@ -1,10 +1,36 @@
 use core::{
     fmt,
-    ops::Div,
+    ops::{Add, Div, Neg, Sub},
 };
 
+macro_rules! impl_add_sub {
+    ($Type: ident) => {
+        impl Add<$Type> for $Type {
+            type Output = $Type;
+            fn add(self, rhs: $Type) -> $Type {
+                $Type(self.0 + rhs.0)
+            }
+        }
+
+        impl Sub<$Type> for $Type {
+            type Output = $Type;
+            fn sub(self, rhs: $Type) -> $Type {
+                $Type(self.0 - rhs.0)
+            }
+        }
+
+        impl Neg for $Type {
+            type Output = $Type;
+            fn neg(self) -> $Type {
+                $Type(-self.0)
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, PartialOrd)]
 pub struct Volts(pub f64);
+impl_add_sub!(Volts);
 
 impl fmt::Display for Volts {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -21,6 +47,7 @@ impl Div<Ohms> for Volts {
 
 #[derive(Debug, Clone, Copy, PartialEq, PartialOrd)]
 pub struct Amps(pub f64);
+impl_add_sub!(Amps);
 
 impl fmt::Display for Amps {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -29,6 +56,7 @@ impl fmt::Display for Amps {
 }
 #[derive(Debug, Clone, Copy, PartialEq, PartialOrd)]
 pub struct Ohms(pub f64);
+impl_add_sub!(Ohms);
 
 impl fmt::Display for Ohms {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {