/*
 * This program drives the speaker on the Wytec EduBase board
 * at 440 Hz using TPM0_CH4 in PWM mode. The speaker is connected
 * to PTC8.
 */

#include "MKL25Z4.H"

int main (void) {
    SIM->SCGC5 |= 0x0800;       /* enable clock to Port C */
    PORTC->PCR[8] = 0x0300;     /* PTC8 used by TPM0 */

    SIM->SCGC6 |= 0x1000000u;   /* enable clock to TPM0 */
    SIM->SOPT2 |= 0x01000000;   /* use MCGFLLCLK as timer counter clock */
    TPM0->SC = 0;               /* disable timer */
    TPM0->CONTROLS[4].CnSC = 0x20 | 0x08;   /* edge-aligned, pulse high */
    TPM0->MOD = 5956;           /* Set up modulo register for 440Hz */
    TPM0->CONTROLS[4].CnV = 2978;  /* Set up channel value for 50% dutycycle */
    TPM0->SC = 0x0C;            /* enable TPM0 with prescaler /16 */
    
    while (1) {
    }
}