From 9d87c925a9eaa4fc256be3173c14a20d1469472d Mon Sep 17 00:00:00 2001
From: fishsoupisgood <github@madingley.org>
Date: Wed, 9 Sep 2020 11:53:37 +0100
Subject: everything, mostly, working

---
 boiler-monster/stm32/app/pressure.c | 164 ++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 boiler-monster/stm32/app/pressure.c

(limited to 'boiler-monster/stm32/app/pressure.c')

diff --git a/boiler-monster/stm32/app/pressure.c b/boiler-monster/stm32/app/pressure.c
new file mode 100644
index 0000000..f719e4d
--- /dev/null
+++ b/boiler-monster/stm32/app/pressure.c
@@ -0,0 +1,164 @@
+#include "project.h"
+
+#define PRESSURE      GPIO0
+#define PRESSURE_PORT     GPIOA
+#define PRESSURE_CHANNEL  ADC_CHANNEL0
+#define VREF_CHANNEL ADC_CHANNEL17
+
+#define N_SAMPLES 1000
+
+#define T do { printf("%s:%d\r\n",__FILE__,__LINE__); } while (0)
+
+static int pressure;
+
+struct avg {
+	int acc;
+	unsigned n;
+};
+
+static void avg_reset(struct avg *a)
+{
+a->acc=0;
+a->n=0;
+return;
+}
+static void avg_add(struct avg *a, int v)
+{
+a->acc+=v;
+a->n++;
+}
+inline static unsigned avg_n(struct avg *a)
+{
+return a->n;
+}
+
+static int avg_get(struct avg *a)
+{
+if (!a->n) return 0;
+return (a->acc) / (a->n);
+}
+
+
+uint16_t pressure_ch (void)
+{
+  return pressure;
+}
+
+
+static void pressure_calculate (int v,int r)
+{
+  /* r is 1.25 volts, transducer is 0.5V -> 0 psi 4.5V -> 100psi  */
+  /* 100psi is 6.8947573 bar, and we want 256ths of bar */
+
+
+  if (!r) {
+    pressure = 0;
+    //  return;
+  } else {
+    pressure = ((v * 552) / r) - 221;
+
+    if (pressure < 0) pressure = 0;
+  }
+
+  printf ("QP: %d %d %d\r\n", v, r, (pressure * 100) / 256);
+}
+
+
+
+void pressure_tick(void)
+{
+static unsigned state;
+static unsigned backoff=MS_TO_TICKS(1000);
+static unsigned timeout;
+
+static struct avg vref_avg;
+static struct avg pressure_avg;
+
+
+timeout++;
+
+if (backoff) {
+	backoff--;
+	return;
+}
+
+
+switch (state) {
+case 0:
+  adc_off (ADC1);
+  adc_power_on (ADC1);
+  backoff=MS_TO_TICKS(5);
+  state++;
+  break;
+case 1:
+  ADC_CR2 (ADC1) |= ADC_CR2_RSTCAL;
+  backoff=MS_TO_TICKS(2);
+  state++;
+  break;
+case 2:
+  if (ADC_CR2(ADC1) & ADC_CR2_CAL)
+	state=0;
+  ADC_CR2 (ADC1) |= ADC_CR2_CAL;
+  backoff=MS_TO_TICKS(2);
+  state++;
+  break;
+case 3:
+  if (ADC_CR2(ADC1) & ADC_CR2_CAL)
+	state=0;
+  state++;
+
+  avg_reset(&vref_avg);
+  avg_reset(&pressure_avg);
+  break;
+case 4:
+  if (adc_convert_start(VREF_CHANNEL))
+	state=0;
+  else {
+  timeout=0;
+  state++;
+  }
+  break;
+case 5:
+  if (adc_convert_done()) {
+  avg_add(&vref_avg,adc_convert_get());
+  state++;
+  } else if (timeout > MS_TO_TICKS(5)) 
+	state=0;
+  break;
+case 6:
+  if (adc_convert_start(PRESSURE_CHANNEL))
+	state=0;
+  else {
+  timeout=0;
+  state++;
+  }
+  break;
+case 7:
+  if (adc_convert_done()) {
+  avg_add(&pressure_avg,adc_convert_get());
+
+  if (avg_n(&pressure_avg)<N_SAMPLES)
+	state=4;
+  else
+	state++;
+  } else if (timeout > MS_TO_TICKS(5)) 
+	state=0;
+  break;
+case 8:
+  pressure_calculate(avg_get(&pressure_avg),avg_get(&vref_avg));
+  state=0;
+  break;
+}
+
+}
+
+
+
+void pressure_init (void)
+{
+  MAP_ANALOG (PRESSURE);
+}
+
+
+
+
-- 
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