analog

firmware/Makefile

@@ -119,9 +119,10 @@ CSRC = $(ALLCSRC) cfg/board.c
 # C++ sources that can be compiled in ARM or THUMB mode depending on the global
 # setting.
 CPPSRC = $(ALLCPPSRC) \
-          pwm.cpp \
+          analog_input.cpp \
           can.cpp \
           can_helper.cpp \
+          pwm.cpp \
           main.cpp
 
 # List ASM source files here.

firmware/analog_input.cpp

@@ -0,0 +1,41 @@
+#include "analog_input.h"
+
+#include "hal.h"
+
+#define ADC_OVERSAMPLE 8
+
+static adcsample_t adcBuffer[3 * ADC_OVERSAMPLE];
+
+ADCConversionGroup convGroup =
+{
+    false, 3, nullptr, nullptr,
+    0,                  // CFGR1
+    ADC_TR(0, 0),       // TR
+    ADC_SMPR_SMP_28P5,      // SMPR
+    ADC_CHSELR_CHSEL0 | ADC_CHSELR_CHSEL1 | ADC_CHSELR_CHSEL2
+};
+
+static float AverageSamples(adcsample_t* buffer, size_t idx)
+{
+    uint32_t sum = 0;
+
+    for (size_t i = 0; i < ADC_OVERSAMPLE; i++)
+    {
+        sum += buffer[idx];
+        idx += ADC_OVERSAMPLE;
+    }
+
+    return (float)sum / ADC_OVERSAMPLE;
+}
+
+AnalogResult AnalogSample()
+{
+    adcConvert(&ADCD1, &convGroup, adcBuffer, ADC_OVERSAMPLE);
+
+    return
+    {
+        .NernstVoltage = AverageSamples(adcBuffer, 0),
+        .VirtualGroundVoltage = AverageSamples(adcBuffer, 1),
+        .PumpCurrentVoltage = AverageSamples(adcBuffer, 2),
+    };
+}

firmware/analog_input.h

@@ -0,0 +1,10 @@
+#pragma once
+
+struct AnalogResult
+{
+    float NernstVoltage;
+    float VirtualGroundVoltage;
+    float PumpCurrentVoltage;
+};
+
+AnalogResult AnalogSample();

firmware/main.cpp

@@ -1,6 +1,7 @@
 #include "ch.h"
 #include "hal.h"
 
+#include "analog_input.h"
 #include "can.h"
 #include "pwm.h"
 
@@ -14,7 +15,7 @@ Pwm pumpDac(PWMD3, 1, 48000000, 1024);
 /*
  * Application entry point.
  */
-int main(void) {
+int main() {
     halInit();
     chSysInit();
 
@@ -27,6 +28,8 @@ int main(void) {
     pumpDac.SetDuty(0.4f);
 
     while (true) {
+        auto result = AnalogSample();
+
         // dummy data
         SendCanData(0.5f, 300);
         chThdSleepMilliseconds(10);