Commit 0af72f0d authored by Birte Kristina Friesel's avatar Birte Kristina Friesel
Browse files

mpu9250_motionlog: measure VCC

parent 098fd9b5

src/app/mpu9250_motionlog/main.cc

+20 −0
Original line number Diff line number Diff line
@@ -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);

	}