lightFSM.h

// GistID: 105a8238cde06b80a8a7
#ifndef LIGHT_FSM
#define LIGHT_FSM

#define G_WEST      0
#define W_WEST      1
#define G_SOUTH     2
#define W_SOUTH     3
#define WALK        4
#define D_WALK_ON   5
#define D_WALK_OFF  6

struct State {  
  // A structure to represent light states and given transitions
  
  unsigned long TrafficOutput;  // 6 bits for each traffic light
  unsigned long WalkOutput;     // 2 bits for walk/don'tWalk
  unsigned long Time;           // Duration of state in 10*ms
  unsigned long Next[8];        // Indices to next state traversal
};

typedef const struct State FSMState;

FSMState FSM[7] = { //0x00        0x01        0x02        0x03        0x04      0x05      0x06      0x07
  {0x0C, 0x02, 10,  G_WEST,       G_WEST,     W_WEST,     W_WEST,     W_WEST,   W_WEST,   W_WEST,   W_WEST},
  {0x14, 0x02, 5,   G_SOUTH,      G_SOUTH,    G_SOUTH,    G_SOUTH,    WALK,     WALK,     WALK,     G_SOUTH},
  {0x21, 0x02, 10,  G_SOUTH,      W_SOUTH,    G_SOUTH,    W_SOUTH,    W_SOUTH,  W_SOUTH,  W_SOUTH,  W_SOUTH},
  {0x22, 0x02, 5,   G_WEST,       G_WEST,     G_WEST,     G_WEST,     WALK,     WALK,     WALK,     WALK},
  {0x24, 0x08, 2,   D_WALK_ON,    D_WALK_ON,  D_WALK_ON,  D_WALK_ON,  WALK,     WALK,     WALK,     D_WALK_ON},
  {0x24, 0x02, 5,   D_WALK_OFF,   D_WALK_OFF, D_WALK_OFF, D_WALK_OFF, WALK,     WALK,     WALK,     D_WALK_OFF},
  {0x24, 0x00, 5,   D_WALK_ON,    G_WEST,     G_SOUTH,    G_SOUTH,    WALK,     WALK,     WALK,     G_WEST}
};
  
#endif

portinit.c

// GistID: 105a8238cde06b80a8a7
#ifndef PORT_INIT
#define PORT_INIT

#include "portinit.h"
#include "tm4c123gh6pm.h"

/*
 * Initialize Port B to be used for traffic lights. Bits 0 through 5 are used to
 * signal active light for GYRG|YR. This function has no input or output but
 * does affect registers related to Port B including the clock.
 */
void PortB_Init(void)
{
  volatile unsigned long delay;
  
  SYSCTL_RCGC2_R |= 0x2;
  delay = SYSCTL_RCGC2_R;
  
  GPIO_PORTB_AMSEL_R  = 0x000000;
  GPIO_PORTB_PCTL_R   = 0x000000;
  GPIO_PORTB_DIR_R    = 0x00003F;
  GPIO_PORTB_AFSEL_R  = 0x000000;
  GPIO_PORTB_PUR_R    = 0x000000;
  GPIO_PORTB_DEN_R    = 0x00003F;
  
}

/*
 * Initialize Port E to be used for traffic/pedestrian sensors. Bits 0 through 2
 * are used for E/W Sensor | N/S Sensor |Pedestrian.
 */
void PortE_Init(void)
{
  volatile unsigned long delay;
  
  SYSCTL_RCGC2_R |= 0x10;
  delay = SYSCTL_RCGC2_R;
  
  GPIO_PORTE_AMSEL_R  = 0x000000;
  GPIO_PORTE_PCTL_R   = 0x000000;
  GPIO_PORTE_DIR_R    &= ~0x000007;
  GPIO_PORTE_AFSEL_R  = 0x000000;
  GPIO_PORTE_PUR_R    = 0x000000;
  GPIO_PORTE_DEN_R    |= 0x000007;
  
}

/*
 * A helper function to enable Port F to allow manipulation of the on board
 * LED's to signal the pedestrian lights. We use bits 3 and 1 to for WALK and DO
 * NOT WALK respectively.
 */
void PortF_Init(void)
{
  volatile unsigned long delay;
  
  SYSCTL_RCGC2_R      |= 0x00000020;
  delay = SYSCTL_RCGC2_R;
  
  GPIO_PORTF_LOCK_R   = 0x4C4F434B;
  GPIO_PORTF_CR_R     = 0x0000001F;
  
  GPIO_PORTF_AMSEL_R  = 0x00000000;
  GPIO_PORTF_PCTL_R   = 0x00000000;
  GPIO_PORTF_DIR_R    = 0x0000000A;
  GPIO_PORTF_AFSEL_R  = 0x00000000;
  GPIO_PORTF_PUR_R    = 0x00000000;
  GPIO_PORTF_DEN_R    = 0x0000000A;

}

#endif

portinit.h

// GistID: 105a8238cde06b80a8a7
#ifndef PORT_INIT
#define PORT_INIT

void PortB_Init(void);
void PortE_Init(void);
void PortF_Init(void);

#endif

systick.c

// GistID: 105a8238cde06b80a8a7
#include "systick.h"

// Enable systick timer
void SysTick_Init(void)
{
  NVIC_ST_CTRL_R = 0;
  NVIC_ST_CTRL_R = 0x00000005;
}

// A simple block on systick counter of given value
void SysTick_Wait(unsigned long delay){
  
  
  NVIC_ST_RELOAD_R  = delay-1;
  NVIC_ST_CURRENT_R = 0;
  
  while((NVIC_ST_CTRL_R&0x00010000)==0);
}

// A wrapper for blocking on 10ms increments
void SysTick_Wait10ms(unsigned long delay)
{
  
  unsigned long i;
  
  for (i=0; i < delay; i++) {
    SysTick_Wait(SYSTICK_TEN_MS_COUNT);
  }
  
}

systick.h

// GistID: 105a8238cde06b80a8a7
#ifndef SYSTICK_FUNC
#define SYSTICK_FUNC

#include "tm4c123gh6pm.h"
#define SYSTICK_TEN_MS_COUNT 800000

// Declare Systick Functions
void SysTick_Init(void);
void SysTick_Wait10ms(unsigned long);

#endif

TableTrafficLight.c

// GistID: 105a8238cde06b80a8a7
#include "TExaS.h"
#include "tm4c123gh6pm.h"

#include "systick.h"
#include "portinit.h"
#include "lightFSM.h"

// FUNCTION PROTOTYPES: Each subroutine defined
void DisableInterrupts(void); // Disable interrupts
void EnableInterrupts(void);  // Enable interrupts

int main(void)
{ 
  
  unsigned char S;
  unsigned long INPUT;
  
  TExaS_Init(SW_PIN_PE210, LED_PIN_PB543210); // activate grader and set system clock to 80 MHz
  EnableInterrupts();

  SysTick_Init();
  
  PortB_Init();
  PortE_Init();
  PortF_Init();
  
  // Initial State is 0
  S = 0;
  
  while(1){
    
    // Write light state to GPIO Ports
    GPIO_PORTB_DATA_R = FSM[S].TrafficOutput;
    GPIO_PORTF_DATA_R = FSM[S].WalkOutput;
    
    // Wait duration
    SysTick_Wait10ms(FSM[S].Time);
    
    // Obtain input state
    INPUT = GPIO_PORTE_DATA_R&0x07;
    
    // Move to next state given input value
    S = FSM[S].Next[INPUT];
  }
}

TExaS.h

// GistID: 105a8238cde06b80a8a7
#ifndef SYSTICK_FUNC
#define SYSTICK_FUNC

#include "tm4c123gh6pm.h"
#define SYSTICK_TEN_MS_COUNT 800000

// Declare Systick Functions
void SysTick_Init(void);
void SysTick_Wait10ms(unsigned long);

#endif