frdm-kl25z voltimeter test

main.c

/* p7_1.c: A to D conversion of channel 0
 * This program converts the analog input from channel 0 (PTE20)
 * using software trigger continuously.
 * Bits 10-8 are used to control the tri-color LEDs. LED code is
 * copied from p2_7. Connect a potentiometer between 3.3V and
 * ground. The wiper of the potentiometer is connected to PTE20.
 * When the potentiometer is turned, the LEDs should change color.
 */
#include <MKL25Z4.h>
#include "fsl_debug_console.h"

void ADC0_init(void);

int main(void) {
	uint16_t result;
	float volt;

	ADC0_init(); /* Configure ADC0 */

	while (1) {
		ADC0->SC1[0] = 0; /* start conversion on channel 0 */
		while (!(ADC0->SC1[0] & 0x80)) {
		} /* wait for conversion complete */
		result = ADC0->R[0]; /* read conversion result and clear COCO flag */
		volt = (result * 3.3) / sizeof(uint16_t);

		PRINTF("ADC value: %i\tVolt: %.2f", result, volt);
	}
}
void ADC0_init(void) {
	SIM->SCGC5 |= 0x2000; /* clock to PORTE */
	PORTE->PCR[20] = 0; /* PTE20 analog input */
	SIM->SCGC6 |= 0x8000000; /* clock to ADC0 */
	ADC0->SC2 &= ~0x40; /* software trigger */

	// TODO: Figure this out. Not sure what this values mean. Consider checking out the ADC component.
	/* clock div by 4, long sample time, single ended 12 bit, bus clock */
	ADC0->CFG1 = 0x40 | 0x10 | 0x4c | 0x00;
}