#include "stm32f30x_conf.h" // STM32 config
#include "30021_io.h" // Input/output library for this course


void init_board();
char readJoystick();

void init_board(void){
RCC->AHBENR |= RCC_AHBPeriph_GPIOA;         // Enable clock for GPIO Port
RCC->AHBENR |= RCC_AHBPeriph_GPIOB;
RCC->AHBENR |= RCC_AHBPeriph_GPIOC;

GPIOA -> MODER &=~  (0x00000003 << (4 * 2)); //CLEAR REGISTER A PA4
GPIOB -> MODER &=~  (0x00000003 << (0 * 2)); //CLEAR REGISTER B PB0
GPIOB -> MODER &=~  (0x00000003 << (5 * 2)); //CLEAR REGISTER B PB5
GPIOC -> MODER &=~  (0x00000003 << (0 * 2)); //CLEAR REGISTER C PC0
GPIOC -> MODER &=~  (0x00000003 << (1 * 2)); //CLEAR REGISTER C PC1

GPIOA -> PUPDR &=~   (0x00000003 << (4 * 2)); //clear pull register
GPIOB -> PUPDR &=~   (0x00000003 << (0 * 2)); //clear pull register
GPIOB -> PUPDR &=~   (0x00000003 << (5 * 2)); //clear pull register
GPIOC -> PUPDR &=~   (0x00000003 << (0 * 2)); //clear pull register
GPIOC -> PUPDR &=~   (0x00000003 << (1 * 2)); //clear pull register

GPIOA -> PUPDR |=  (0x00000002 << (4 * 2)); //Set Pulldown A PA4
GPIOB -> PUPDR |=  (0x00000002 << (0 * 2)); //Set Pulldown B PB0
GPIOB -> PUPDR |=  (0x00000002 << (5 * 2)); //Set Pulldown B PB5
GPIOC -> PUPDR |=  (0x00000002 << (0 * 2)); //Set Pulldown C PC0
GPIOC -> PUPDR |=  (0x00000002 << (1 * 2)); //Set Pulldown C PC1
}

char readJoystick(void){
    char joystick = 0x00;

    if(GPIOA->IDR & (0x0001 << 4)){joystick=0b00000001;}//up
    if(GPIOB->IDR & (0x0001 << 0)){joystick=0b00000010;}//down
    if(GPIOC->IDR & (0x0001 << 1)){joystick=0b00000100;}//left
    if(GPIOC->IDR & (0x0001 << 0)){joystick=0b00001000;}//right
    if(GPIOB->IDR & (0x0001 << 5)){joystick=0b00010000;}//center

    return(joystick);
}

int main(void){

    init_board();

    init_usb_uart( 9600 );

    int8_t check = 0;
    char position = 0;

        while(1){

        position = readJoystick();

        if(check==0){
            if(position ==  0b00000001){printf("up");}
            if(position ==  0b00000010){printf("down");}
            if(position ==  0b00000100){printf("left");}
            if(position ==  0b00001000){printf("right");}
            if(position ==  0b00010000){printf("Center");}
            printf("\n");
            check =  1;
        }

        if(position==0x00){
            check=0;
        }
    }
}