// 0.Documentation Section

// SoftSound.c

// Runs on LM4F120 or TM4C123

// Use the SysTick timer to request interrupts at 500Hz.

// Jonathan Valvano

// November 3, 2013

#include "PLL.h"

#include <stdio.h>

#include "tm4c123gh6pm.h"

// Constant declarations to access port registers using

// symbolic names instead of addresses

void SysTick_Wait10ms(unsigned long delay);

void DisableInterrupts(void); // Disable interrupts

void EnableInterrupts(void); // Enable interrupts

void WaitForInterrupt(void); // low power mode

void Port_Init(void); // start sound output

void SysInit(void);

void SysLoad(unsigned long period);

unsigned long int j;

unsigned long int k;

unsigned int i=0;

// 3. Subroutines Section

// MAIN: Mandatory for a C Program to be executable

int main(void){

PLL_Init();

// 80 MHz

// initialize output and interrupts

SysInit();

Port_Init();

// EnableInterrupts();

/*Initialize ports and timers*/

while(1)

{

for(j=80000;j<=160000;j=j+8000)

{

for(k=0;k<=3;k++)

{

GPIO_PORTA_DATA_R|=0x20;

SysLoad(j);

GPIO_PORTA_DATA_R&=~(0x20);

SysLoad(1600000-j);

}

}

}

}

// **************Port_Init*********************

// Initialize SysTick periodic interrupts

// Input: none

// Output: none

void Port_Init(void){ unsigned long volatile delay;

/*PORT A or PORTF Inititalisation*/

printf("in loop");

SYSCTL_RCGC2_R |= 0x01; // 1) activate clock for Port A

delay = SYSCTL_RCGC2_R; // allow time for clock to start

GPIO_PORTA_AMSEL_R &=~ 0x20; // 3) disable analog on PA

GPIO_PORTA_PCTL_R &=~ 0x00F00000; // 4) PCTL GPIO on PF4-0

GPIO_PORTA_DIR_R |= 0x20; // 5) PA6 as output

GPIO_PORTA_AFSEL_R &= ~0x20; // 6) disable alt funct on PA7-0

//GPIO_PORTA_PUR_R |= 0x00; // disable pull-up

GPIO_PORTA_DEN_R |= 0x20; // 7) enable digital I/O on PF4-0

}

void SysLoad(unsigned long period){

NVIC_ST_RELOAD_R = period-1; // number of counts to wait

NVIC_ST_CURRENT_R = 0; // any value written to CURRENT clears

while((NVIC_ST_CTRL_R&0x00010000)==0){ // wait for count flag

}

}

void SysInit(void){

NVIC_ST_CTRL_R = 0; // disable SysTick during setup

NVIC_ST_CTRL_R = 0x00000005;

}

void SysTick_Wait10ms(unsigned long delay){

unsigned long i;

for(i=0; i<=delay; i++){

SysLoad(800000); // wait 10ms

}

}