Input_Output_TIVAC.c

// 0.Documentation Section 
// main.c
// Runs on LM4F120 or TM4C123
// C6_InputOutput, Input from PF4, output to PF2 (blue LED)
// Authors: Daniel Valvano, Jonathan Valvano and Ramesh Yerraballi
// Date: July 8, 2013

// LaunchPad built-in hardware
// SW1 left switch is negative logic PF4 on the Launchpad
// SW2 right switch is negative logic PF0 on the Launchpad
// red LED connected to PF1 on the Launchpad
// blue LED connected to PF2 on the Launchpad
// green LED connected to PF3 on the Launchpad

// 1. Pre-processor Directives Section
// Constant declarations to access port registers using 
// symbolic names instead of addresses
#define GPIO_PORTF_DATA_R       (*((volatile unsigned long *)0x400253FC))
#define GPIO_PORTF_DIR_R        (*((volatile unsigned long *)0x40025400))
#define GPIO_PORTF_AFSEL_R      (*((volatile unsigned long *)0x40025420))
#define GPIO_PORTF_PUR_R        (*((volatile unsigned long *)0x40025510))
#define GPIO_PORTF_DEN_R        (*((volatile unsigned long *)0x4002551C))
#define GPIO_PORTF_LOCK_R       (*((volatile unsigned long *)0x40025520))
#define GPIO_PORTF_CR_R         (*((volatile unsigned long *)0x40025524))
#define GPIO_PORTF_AMSEL_R      (*((volatile unsigned long *)0x40025528))
#define GPIO_PORTF_PCTL_R       (*((volatile unsigned long *)0x4002552C))
#define SYSCTL_RCGC2_R          (*((volatile unsigned long *)0x400FE108))
// 2. Declarations Section
//   Global Variables

//   Function Prototypes
void PortF_Init(void);

// 3. Subroutines Section
// MAIN: Mandatory for a C Program to be executable
int main(void){    

  while(1){

  }
}
// 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) F clock
  delay = SYSCTL_RCGC2_R;           // delay   
  GPIO_PORTF_LOCK_R = 0x4C4F434B;   // 2) unlock PortF PF0  
  GPIO_PORTF_CR_R = 0x1F;           // allow changes to PF4-0       
  GPIO_PORTF_AMSEL_R = 0x00;        // 3) disable analog function
  GPIO_PORTF_PCTL_R = 0x00000000;   // 4) GPIO clear bit PCTL  
  GPIO_PORTF_DIR_R = 0x0E;          // 5) PF4,PF0 input, PF3,PF2,PF1 output   
  GPIO_PORTF_AFSEL_R = 0x00;        // 6) no alternate function
  GPIO_PORTF_PUR_R = 0x11;          // enable pullup resistors on PF4,PF0       
  GPIO_PORTF_DEN_R = 0x1F;          // 7) enable digital pins PF4-PF0        
}
// Color    LED(s) PortF
// dark     ---    0
// red      R--    0x02
// blue     --B    0x04
// green    -G-    0x08
// yellow   RG-    0x0A
// sky blue -GB    0x0C
// white    RGB    0x0E
// pink     R-B    0x06