/* This program drives the speaker on the EduPad board
 * at 440 Hz using WTIMER0A in PWM mode.
 *
 * Built and tested with Keil MDK-ARM v5.24a and TM4C_DFP v1.1.0
 */

#include "TM4C123.h"

int main(void) {
    SYSCTL->RCGCGPIO |= 0x04;       // enable clock to GPIOC
    SYSCTL->RCGCWTIMER |= 0x01;     // enable clock to Timer Block 0

    // enable PORTC 4 as output
    GPIOC->AMSEL &= ~0x10;          // disable analog function of PORTC 4
    GPIOC->DIR |= 0x10;             // set PORTC 4 as output pins
    GPIOC->DEN |= 0x10;             // set PORTC 4 as digital pins
    GPIOC->AFSEL |= 0x10;           // enable alternate function
    GPIOC->PCTL &= ~0x000F0000;     // clear alternate function for PORTC 4
    GPIOC->PCTL |=  0x00070000;     // set PORTC 4 alternate function to WTIMER
    
    WTIMER0->CTL &= ~1;             // disable WTIMER0A during setup
    WTIMER0->CFG = 4;               // configure as 32-bit timer mode
    WTIMER0->TAMR = 0x0A;           // down-count, PWM-periodic mode
    WTIMER0->TAILR = 113635;        // set frequency to 440 Hz
    WTIMER0->TAMATCHR = 56818;      // set duty cycle to 50%
    WTIMER0->CTL |= 1;              // enable WTIMER0A

    while(1) {
    }
}