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Diffstat (limited to 'src/kernel/ao_convert_volt.c')
-rw-r--r--src/kernel/ao_convert_volt.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/src/kernel/ao_convert_volt.c b/src/kernel/ao_convert_volt.c
index 8556d423..7afc34bf 100644
--- a/src/kernel/ao_convert_volt.c
+++ b/src/kernel/ao_convert_volt.c
@@ -17,17 +17,23 @@
#include "ao.h"
-#define scale(v,p,m) ((int32_t) (v) * (AO_ADC_REFERENCE_DV * ((p) + (m))) / (AO_ADC_MAX * (m)))
+#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 scale(v,p,m) (((int32_t) (v) * MUL(p,m) + ADD(p,m)) / DIV(p,m))
+#if HAS_APRS || HAS_BATTERY_REPORT
int16_t
ao_battery_decivolt(int16_t adc)
{
return scale(adc, AO_BATTERY_DIV_PLUS, AO_BATTERY_DIV_MINUS);
}
+#endif
+#if HAS_APRS
int16_t
ao_ignite_decivolt(int16_t adc)
{
return scale(adc, AO_IGNITE_DIV_PLUS, AO_IGNITE_DIV_MINUS);
}
-
+#endif