// 0.Documentation Section

//

// Runs on LM4F120 or TM4C123

// Use the SysTick timer to request interrupts .

// Jonathan Valvano

// November 3, 2013

#include "PLL.h"

#include "tm4c123gh6pm.h"

void DisableInterrupts(void); // Disable interrupts

void EnableInterrupts(void); // Enable interrupts

void WaitForInterrupt(void); // low power mode

void PortA_Init(void); // start sound output

void SysInit(void); //initialize SysTick timer

void SysLoad(unsigned long period); //Load reload value

int main(void){

PLL_Init();

PortA_Init();

SysInit();

SysLoad(40000);

while(1){

}

// initialize output and interrupts

//EnableInterrupts();

/*Initialize necessary ports and timers here*/

}

// **************Sound_Init*********************

// Initialize SysTick periodic interrupts

// Input: none

// Output: none

void PortA_Init(void){ unsigned long volatile delay;

/*PORT Initialization*/

SYSCTL_RCGC2_R |= 0x01; // Port A clock

delay = SYSCTL_RCGC2_R; // wait 3-5 bus cycles

GPIO_PORTA_DIR_R |= 0x40; // PA6 output

GPIO_PORTA_AFSEL_R &= ~0x40; // not alternative

GPIO_PORTA_AMSEL_R &= ~0x40; // no analog

GPIO_PORTA_PCTL_R &= ~0x0F000000; // bits for PA6

GPIO_PORTA_DEN_R |= 0x40;

}

void SysLoad(unsigned long period){

NVIC_ST_RELOAD_R = period -1;

}

void SysInit(void){

NVIC_ST_CTRL_R = 0;

NVIC_ST_CURRENT_R = 0; // any write to current clears it

NVIC_SYS_PRI3_R = NVIC_SYS_PRI3_R&0x00FFFFFF; // priority 0

NVIC_ST_CTRL_R = 0x00000007; // enable with core clock and interrupts

}

// Interrupt service routine

//

void SysTick_Handler(void){

GPIO_PORTA_DATA_R ^= 0x40;

/*Your code goes here*/

}