[edX]Embedded Systems – Shape The World ずっと受けたかった組み込みソフト開発の授業

#define PA5   (*((volatile unsigned long *)0x40004080))

data = (*((volatile unsigned long *)0x40004080));
data = 0x40004080;
data = (*0x40004080);

# Register Write
PA5 = 0x20;
# Register Read
data = PA5;

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 &= ~0x11;      // 5.1) PF4,PF0 input,
  GPIO_PORTF_DIR_R |= 0x08;       // 5.2) PF3 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       
}

// 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
unsigned long SW1; // input from PF4
unsigned long SW2; // input from PF0

// Subroutine to initialize port F pins for input and output
// PF4 is input SW1 and PF2 is output Blue LED
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 &= ~0x11;      // 5.1) PF4,PF0 input,
  GPIO_PORTF_DIR_R |= 0x08;       // 5.2) PF3 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       
}

void FlashSOS(void){
  //S
  GPIO_PORTF_DATA_R |= 0x08;  delay(1);
  GPIO_PORTF_DATA_R &= ~0x08; delay(1);
  GPIO_PORTF_DATA_R |= 0x08;  delay(1);
  GPIO_PORTF_DATA_R &= ~0x08; delay(1);
  GPIO_PORTF_DATA_R |= 0x08;  delay(1);
  GPIO_PORTF_DATA_R &= ~0x08; delay(1);
  //O
  GPIO_PORTF_DATA_R |= 0x08; delay(4);
  GPIO_PORTF_DATA_R &= ~0x08;delay(4);
  GPIO_PORTF_DATA_R |= 0x08; delay(4);
  GPIO_PORTF_DATA_R &= ~0x08;delay(4);
  GPIO_PORTF_DATA_R |= 0x08; delay(4);
  GPIO_PORTF_DATA_R &= ~0x08;delay(4);
  //S
  GPIO_PORTF_DATA_R |= 0x08; delay(1);
  GPIO_PORTF_DATA_R &= ~0x08;delay(1);
  GPIO_PORTF_DATA_R |= 0x08; delay(1);
  GPIO_PORTF_DATA_R &= ~0x08;delay(1);
  GPIO_PORTF_DATA_R |= 0x08; delay(1);
  GPIO_PORTF_DATA_R &= ~0x08;delay(1);
  delay(10); // Delay for 5 secs in between flashes
}