From: Keith Packard <keithp@keithp.com>
Date: Sat, 22 Jul 2023 06:19:06 +0000 (-0700)
Subject: altos: Compute igniter good/bad thresholds using 3.5V value
X-Git-Tag: 1.9.17~1^2~8
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=70481772386d556b8a7981da38a03f5c9b181a7c

altos: Compute igniter good/bad thresholds using 3.5V value

Instead of requiring each product to set the ADC values for good/bad
igniters, compute them based upon a 3.5V value using the ADC
characteristics already present in ao_pins.h.

This changes the threshold used on LPC parts from 400 (0.189V) to
7388.

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/kernel/ao.h b/src/kernel/ao.h
index b3f780f5..edfbbb87 100644
--- a/src/kernel/ao.h
+++ b/src/kernel/ao.h
@@ -982,4 +982,26 @@ void ao_ms5607_init(void);
 
 #include <ao_arch_funcs.h>
 
+/*
+ * dv = (sensor * (p+m) * ref_dv)/ (max * m)
+ * value * (max * m) = (sensor * (p+m) * ref)
+ * value * (max * m) / ((p+m) * ref) = sensor
+ */
+
+#define AO_DV_MUL(p,m) ((int32_t) AO_ADC_MAX * (m))
+#define AO_DV_DIV(p,m) ((int32_t) AO_ADC_REFERENCE_DV * ((p) + (m)))
+#define AO_DV_ADD(p,m) (AO_DV_DIV(p,m) / 2)
+
+#define ao_decivolt_to_adc(dv, p, m) \
+	((int16_t) (((int32_t) (dv) * AO_DV_MUL(p,m) + AO_DV_ADD(p,m)) / AO_DV_DIV(p,m)))
+
+#define AO_IGNITER_CLOSED_DV	35
+#define AO_IGNITER_OPEN_DV	10
+
+#undef AO_IGNITER_OPEN
+#undef AO_IGNITER_CLOSED
+
+#define AO_IGNITER_OPEN ao_decivolt_to_adc(AO_IGNITER_OPEN_DV, AO_IGNITE_DIV_PLUS, AO_IGNITE_DIV_MINUS)
+#define AO_IGNITER_CLOSED ao_decivolt_to_adc(AO_IGNITER_CLOSED_DV, AO_IGNITE_DIV_PLUS, AO_IGNITE_DIV_MINUS)
+
 #endif /* _AO_H_ */
diff --git a/src/kernel/ao_convert_volt.c b/src/kernel/ao_convert_volt.c
index c5dfd22d..1f04df64 100644
--- a/src/kernel/ao_convert_volt.c
+++ b/src/kernel/ao_convert_volt.c
@@ -19,8 +19,8 @@
 #include "ao.h"
 
 #define MUL(p,m)	((int32_t) AO_ADC_REFERENCE_DV * ((p) + (m)))
-#define ADD(p,m)	(MUL(p,m)/2)
 #define DIV(p,m)	((int32_t) AO_ADC_MAX * (m))
+#define ADD(p,m)	(DIV(p,m) / 2)
 #define scale(v,p,m)	(((int32_t) (v) * MUL(p,m) + ADD(p,m)) / DIV(p,m))
 
 #if HAS_APRS || HAS_BATTERY_REPORT