28 lines
772 B
C++
28 lines
772 B
C++
|
#include "voltage.h"
|
||
|
|
|
||
|
|
// Pin definitions
|
||
|
|
static const int PIN_VBAT = A0;
|
||
|
|
|
||
|
|
// Voltage divider constants
|
||
|
|
// Divider: 100k upper (to Vin), 47k lower (to GND)
|
||
|
|
// Vout = Vin * (47k / (100k + 47k)) = Vin * 0.3197
|
||
|
|
// At 12V: ADC sees 3.84V | At 14.4V: ADC sees 4.60V
|
||
|
|
static const float DIVIDER_RATIO = 47.0 / (100.0 + 47.0); // ~0.3197
|
||
|
|
static const float ADC_REF = 5.0;
|
||
|
|
static const int ADC_MAX = 1023;
|
||
|
|
|
||
|
|
void voltage_init() {
|
||
|
|
// analogRead doesn't need explicit pinMode, but here for future config
|
||
|
|
// e.g., could switch to internal 1.1V reference for different range
|
||
|
|
}
|
||
|
|
|
||
|
|
int voltage_read_raw() {
|
||
|
|
return analogRead(PIN_VBAT);
|
||
|
|
}
|
||
|
|
|
||
|
|
float voltage_read() {
|
||
|
|
int raw = voltage_read_raw();
|
||
|
|
float vDivider = (raw / (float)ADC_MAX) * ADC_REF;
|
||
|
|
return vDivider / DIVIDER_RATIO;
|
||
|
|
}
|