/* p11_2.c Using TCC0 PWM Output
 *
 * This program uses TCC0 to generate periodic waveform outputs.
 * The GCLK_TCC0 is running at 1 MHz. Prescaler is not used so
 * the timer counter clock is 1 MHz as well.
 * TCC0 is set up to run 24-bit Normal PWM mode, in
 * which the counter counts up to PER as the TOP value and wraps
 * around. The channel 0 output is set when on wraparound
 * and clear on match of CC0.
 * PER is set to 16,666-1 which gives the output of channel 0
 * 1,000,000 / 16,666 = 60 Hz.
 * CC10 is set to 1/3 of the value of PER so that the outputs of
 * channel 1 has 33.3% dutycycle.
 * PB30 is used for TCC0 output channel 0 (TCC0/WO[0]).
 *
 * Tested with Atmel Studio 7 v7.0.1006 and Keil MDK-ARM v5.21a.
 */

#include "samd21.h"

unsigned char* ARRAY_PORT_PINCFG1 = (unsigned char*)&REG_PORT_PINCFG1;
unsigned char* ARRAY_PORT_PMUX1 = (unsigned char*)&REG_PORT_PMUX1;

int main (void) {
    REG_GCLK_CLKCTRL = 0x401A;      /* GCLK0 -> TCC0, TCC1 */
    REG_PM_APBCMASK |= 0x00000100;  /* enable TCC0 Clock in PM */
    REG_TCC0_CTRLA = 1;             /* reset */
    while (REG_TCC0_CTRLA & 1) {}   /* wait till out of reset */
    REG_TCC0_WAVE = 2;              /* Normal PWM */
    REG_TCC0_PER = 16666 - 1;       /* period */
    REG_TCC0_CC0 = 5555 - 1;        /* pulse width */
    REG_TCC0_CTRLA |= 2;            /* enable */

    ARRAY_PORT_PINCFG1[30] |= 1;    /* make PB30 output for TCC0 */
    ARRAY_PORT_PMUX1[15] = 0x04;    /* PB30 = TCC0/WO[0] */
	
    while(1) {
    }
}