main: connect adc/sh/pid/dac, split out into mod channel_state

src/ad7172/mod.rs

@@ -19,6 +19,8 @@ pub const SPI_MODE: spi::Mode = spi::Mode {
 /// 2 MHz
 pub const SPI_CLOCK: MegaHertz = MegaHertz(2);
 
+pub const MAX_VALUE: u32 = 0xFF_FFFF;
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum AdcError<SPI> {
     SPI(SPI),

src/channel_state.rs

@@ -0,0 +1,40 @@
+use smoltcp::time::Instant;
+use crate::{ad5680, ad7172, pid, steinhart_hart as sh};
+
+
+pub struct ChannelState {
+    pub adc_data: Option<i32>,
+    pub adc_time: Instant,
+    pub dac_value: u32,
+    pub pid_enabled: bool,
+    pub pid: pid::Controller,
+    pub sh: sh::Parameters,
+}
+
+impl Default for ChannelState {
+    fn default() -> Self {
+        ChannelState {
+            adc_data: None,
+            adc_time: Instant::from_secs(0),
+            dac_value: 0,
+            pid_enabled: false,
+            pid: pid::Controller::new(pid::Parameters::default()),
+            sh: sh::Parameters::default(),
+        }
+    }
+}
+
+impl ChannelState {
+    /// Update PID state on ADC input, calculate new DAC output
+    pub fn update_adc(&mut self, now: Instant, adc_data: i32) {
+        self.adc_data = Some(adc_data);
+        self.adc_time = now;
+
+        // Update PID controller
+        let input = (adc_data as f64) / (ad7172::MAX_VALUE as f64);
+        let temperature = self.sh.get_temperature(input);
+        let output = self.pid.update(temperature);
+        self.dac_value = (output * (ad5680::MAX_VALUE as f64)) as u32;
+    }
+}
+

src/main.rs

@@ -44,30 +44,8 @@ use command_parser::{Command, ShowCommand, PwmPin};
 mod timer;
 mod pid;
 mod steinhart_hart;
-use steinhart_hart as sh;
+mod channel_state;
-
+use channel_state::ChannelState;
-
-struct ChannelState {
-    adc_data: Option<i32>,
-    adc_time: Instant,
-    dac_value: u32,
-    pid_enabled: bool,
-    pid: pid::Controller,
-    sh: sh::Parameters,
-}
-
-impl Default for ChannelState {
-    fn default() -> Self {
-        ChannelState {
-            adc_data: None,
-            adc_time: Instant::from_secs(0),
-            dac_value: 0,
-            pid_enabled: false,
-            pid: pid::Controller::new(pid::Parameters::default()),
-            sh: sh::Parameters::default(),
-        }
-    }
-}
 
 
 const HSE: MegaHertz = MegaHertz(8);
@@ -151,8 +129,20 @@ fn main() -> ! {
                     let data = adc.read_data().unwrap();
 
                     let state = &mut channel_states[usize::from(channel)];
-                    state.adc_data = Some(data);
+                    state.update_adc(instant, data);
-                    state.adc_time = instant;
+
+                    if state.pid_enabled {
+                        // Forward PID output to i_set DAC
+                        match channel {
+                            0 =>
+                                dac0.set(state.dac_value).unwrap(),
+                            1 =>
+                                dac1.set(state.dac_value).unwrap(),
+                            _ =>
+                                unreachable!(),
+                        }
+                    }
+
                     server.for_each(|_, session| session.set_report_pending(channel.into()));
                 });