diff options
| author | Daniel Friesel <derf@finalrewind.org> | 2020-03-08 15:49:58 +0100 |
|---|---|---|
| committer | Daniel Friesel <derf@finalrewind.org> | 2020-03-08 15:49:58 +0100 |
| commit | 0af72f0d9db44381e15f29e8c72fb7f39603ee86 (patch) | |
| tree | b842d812d69d5e5a1cb001c4cc0b9312e6622d50 /src | |
| parent | 098fd9b55d055204b811317f2e117232637a48ab (diff) | |
mpu9250_motionlog: measure VCC
Diffstat (limited to 'src')
| -rw-r--r-- | src/app/mpu9250_motionlog/main.cc | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/app/mpu9250_motionlog/main.cc b/src/app/mpu9250_motionlog/main.cc index 53a8ba6..5165884 100644 --- a/src/app/mpu9250_motionlog/main.cc +++ b/src/app/mpu9250_motionlog/main.cc @@ -23,6 +23,15 @@ int main(void) gpio.setup(); kout.setup(); + // One ADC conversion per four seconds + TCCR1A = 0; + TCCR1B = _BV(CS12) | _BV(CS10); + + // Measure internal 1.1V bandgap using VCC as reference on each Timer 1 overflow + ADMUX = _BV(REFS0) | 0x0e; + ADCSRB = _BV(ADTS2) | _BV(ADTS1); + ADCSRA = _BV(ADEN) | _BV(ADATE) | _BV(ADPS2) | _BV(ADPS1); + if (i2c.setup() != 0) { kout << "I2C setup failed" << endl; return 1; @@ -50,6 +59,17 @@ int main(void) min_ax = min_ay = min_az = 30000; max_ax = max_ay = max_az = -30000; i = 0; + if (ADCSRA & _BV(ADIF)) { + uint8_t adcr_l = ADCL; + uint8_t adcr_h = ADCH; + uint16_t adcr = adcr_l + (adcr_h << 8); + uint16_t vcc = 1100L * 1023 / adcr; + + TIFR1 |= _BV(TOV1); + ADCSRA |= _BV(ADIF); + + kout << "VCC: " << vcc << endl; + } } arch.delay_ms(1); } |