Input_Output_TIVACxxx.c

#include "tm4c123ge6pm.h"
unsigned long In;  // input from PF4

unsigned long Out; // output to PF2 (blue LED)

//   Function Prototypes

void PortF_Init(void);

// 3. Subroutines Section

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

int main(void){    // initialize PF0 and PF4 and make them inputs

  PortF_Init();    // make PF3-1 out (PF3-1 built-in LEDs)

  while(1){

    In = GPIO_PORTF_DATA_R&0x10;   // read PF4 into Sw1

    In = In>>2;                    // shift into position PF2

    Out = GPIO_PORTF_DATA_R;

    Out = Out&0xFB;

    Out = Out|In;

    GPIO_PORTF_DATA_R = Out;        // output

  }

}

// Subroutine to initialize port F pins for input and output

// PF4 is input SW1 and PF2 is output Blue LED

// Inputs: None

// Outputs: None

// Notes: ...

void PortF_Init(void){ volatile unsigned long delay;

  SYSCTL_RCGC2_R |= 0x00000020;     // 1) activate clock for Port F

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

  GPIO_PORTF_LOCK_R = 0x4C4F434B;   // 2) unlock GPIO Port F

  GPIO_PORTF_CR_R = 0x1F;           // allow changes to PF4-0

  // only PF0 needs to be unlocked, other bits can't be locked

  GPIO_PORTF_AMSEL_R = 0x00;        // 3) disable analog on PF

  GPIO_PORTF_PCTL_R = 0x00000000;   // 4) PCTL GPIO on PF4-0

  GPIO_PORTF_DIR_R = 0x0E;          // 5) PF4,PF0 in, PF3-1 out

  GPIO_PORTF_AFSEL_R = 0x00;        // 6) disable alt funct on PF7-0

  GPIO_PORTF_PUR_R = 0x11;          // enable pull-up on PF0 and PF4

  GPIO_PORTF_DEN_R = 0x1F;          // 7) enable digital I/O on PF4-0

}