Traffic_Lights Using Tiva

// ***** 0. Documentation Section *****
// Runs on LM4F120/TM4C123
// Index implementation of a Moore finite state machine to operate a traffic light.
//20 July 2016
//Reference: http://users.ece.utexas.edu/~valvano/

// "don't walk" red light connected to PA2
// "walk" yellow light connected to PA3
// east/west red light connected to PB5
// east/west yellow light connected to PB4
// east/west green light connected to PB3
// north/south facing red light connected to PB2
// north/south facing yellow light connected to PB1
// north/south facing green light connected to PB0
// pedestrian detector connected to PE2 (1=pedestrian present)
// north/south car detector connected to PE1 (1=car present)
// east/west car detector connected to PE0 (1=car present)

// ***** 1. Pre-processor Directives Section *****
#include "tm4c123gh6pm.h"

// ***** 2. Global Declarations Section *****
// FUNCTION PROTOTYPES: Each subroutine defined
void SysTick_Init(void);                         // initialize SysTick Timer
void SysTick_Wait(unsigned long delay1);
void SysTick_Wait10ms(unsigned long delay1);     // waiting time
struct State{
	unsigned long TrafficLights_Cars; //6 bits output to Six LEDs for Cars
	unsigned long TrafficLights_Ped; //2 bits output to two Leds for Pedestrians
	unsigned long Time;    //delay in 10ms units
	unsigned long Next[8]; //next states for inputs 0,1,2,3,4,5,6,7
};
typedef const struct State STyp;
#define Go_West          0   //name of the states
#define Wait_West        1
#define Go_South         2
#define Wait_South       3
#define Walk_Ped         4
#define Hurry_On_Ped1    5
#define Hurry_Off_Ped1   6
#define Hurry_On_Ped2    7
#define Hurry_Off_Ped2   8

//Next[8] array represents 8 inputs and the next state transition
//The first array element represents 000 input, the second represents 001 input and so on upto 111 (eighth input)
//Input bits representation- MSB=Walk Sensor,Middle bit=South Sensor and LSB=West Sensor
//FSM[9]={
//{ouput to Six signal LEDs (TrafficLights_Cars),output to two Pedestrian LEDs (TrafficLights_Ped),Time in 10ms units,Next[8] array elements(next states)},
// ..............
STyp FSM[9]={
		{0x0C,0x04,100,{0,0,1,1,1,1,1,1}},       //state 1
	  {0x14,0x04,50 ,{2,2,2,2,4,4,4,2}},       //state 2
		{0x21,0x04,100,{2,3,2,3,3,3,3,3}},       //state 3
		{0x22,0x04,50 ,{0,0,0,0,4,4,4,4}},       //state 4
		{0x24,0x08,100,{4,5,5,5,4,5,5,5}},       //state 5
		{0x24,0x04,25 ,{6,6,6,6,4,6,6,6}},       //state 6
		{0x24,0x00,10 ,{7,7,7,7,4,7,7,7}},       //state 7
		{0x24,0x04,25 ,{8,8,8,8,4,8,8,8}},       //state 8
		{0x24,0x00,10 ,{0,0,2,0,4,0,2,0}}        //state 9

};
unsigned long S;  //index to the current state
unsigned long Input;
// ***** 3. Subroutines Section *****

int main(void) {
	volatile unsigned long delay;
    SysTick_Init();
	SYSCTL_RCGC2_R=0x13;        //activate clock for port A,E,B
	delay=SYSCTL_RCGC2_R;       // no need to unlock port B,E,A
	GPIO_PORTB_AMSEL_R=0x00;          //disable analog on port B
	GPIO_PORTE_AMSEL_R=0x00;          //disable analog on port E
	GPIO_PORTA_AMSEL_R=0x00;          //disable analog on port A
	GPIO_PORTB_PCTL_R=0x00000000;     //enable regular GPIO
	GPIO_PORTE_PCTL_R=0x00000000;     //enable regular GPIO
	GPIO_PORTA_PCTL_R=0x00000000;     //enable regular GPIO
	GPIO_PORTB_DIR_R=0x3F;            //outputs on PB0-5
	GPIO_PORTE_DIR_R=0x00;            //inputs on PE0-2
	GPIO_PORTA_DIR_R=0x0C;            //outputs on PA2 and PA3
	GPIO_PORTB_AFSEL_R=0x00;          //disable alternate function
	GPIO_PORTE_AFSEL_R=0x00;          //disable alternate function
	GPIO_PORTA_AFSEL_R=0x00;          //disable alternate function
	GPIO_PORTB_DEN_R=0x3F;            //enable digital I/O on PB0-5
	GPIO_PORTE_DEN_R=0x07;            //enable digital I/O on PE0-2
	GPIO_PORTA_DEN_R=0x0C;            //enable digital I/O on PA2 and PA3
	S=Go_West;
		while(1){
			GPIO_PORTB_DATA_R=FSM[S].TrafficLights_Cars;    //set car signal lights
			GPIO_PORTA_DATA_R=FSM[S].TrafficLights_Ped;    //set walk signal lights
			SysTick_Wait10ms(FSM[S].Time);
			Input=GPIO_PORTE_DATA_R;                      //read sensors
			S=FSM[S].Next[Input];
			}

}
void SysTick_Init(void){
  NVIC_ST_CTRL_R = 0;               // disable SysTick during setup
  NVIC_ST_CTRL_R = 0x00000005;      // enable SysTick with core clock
}
// The delay parameter is in units of the 80 MHz core clock. (12.5 ns)
void SysTick_Wait(unsigned long delay1){
  NVIC_ST_RELOAD_R = delay1-1;  // 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
  }
}
// 800000*12.5ns equals 10ms
void SysTick_Wait10ms(unsigned long delay1){
  unsigned long i;
  for(i=0; i<delay1; i++){
    SysTick_Wait(800000);  // wait 10ms
  }
}