Improve lighting C program

explain ： The watchdog timer will reset the whole system automatically , Used to update bug, Systematic self-protection mechanism

** explain ：
commonly CON Is the control input and output
DAT Control the specific register control pin
So just find the corresponding one

Development manuals are important , To be able to search

Cycle lighting procedure

The method of zeroing and setting one can be the same as before to set the desired bit or and
But it's too long to write , This kind of shift is generally used

void delay(volatile int d)
{
    
	while (d--);
}

int main(void)
{
    
	volatile unsigned int *pGPFCON = (volatile unsigned int *)0x56000050;
	// Join in volatile  The system will handle it properly , Will not automatically optimize 
	volatile unsigned int *pGPFDAT = (volatile unsigned int *)0x56000054;

	int val = 0;  /* val: 0b000, 0b111 */
	int tmp;

	/*  Set up GPFCON Give Way GPF4/5/6 Configured as output pin  */
	*pGPFCON &= ~((3<<8) | (3<<10) | (3<<12));
	// Zero clearing 
	*pGPFCON |=  ((1<<8) | (1<<10) | (1<<12));
    // Configuration register 
    
	/*  Cycle on  */
	while (1)
	{
    
		tmp = ~val;
		tmp &= 7;
		*pGPFDAT &= ~(7<<4);
		*pGPFDAT |= (tmp<<4);
		delay(100000);
		val++;
		if (val == 8)
			val =0;
		
	}

	return 0;
}

In addition, the latter uses to define registers as macros , The effect is the same, don't write

Key led Program

#include "s3c2440_soc.h"
// Write the function definition here , You don't have to configure registers all the time 


void delay(volatile int d)
{
    
	while (d--);
}

int main(void)
{
    
	int val1, val2;
	
	/*  Set up GPFCON Give Way GPF4/5/6 Configured as output pin  */
	GPFCON &= ~((3<<8) | (3<<10) | (3<<12));
	GPFCON |=  ((1<<8) | (1<<10) | (1<<12));
// Reset first and then set one 

	/*  To configure 3 Key pins are input pins : * GPF0(S2),GPF2(S3),GPG3(S4) */
	GPFCON &= ~((3<<0) | (3<<4));  /* gpf0,2 */
	GPGCON &= ~((3<<6));  /* gpg3 */

// Directly clear all 

	/*  Cycle on  */
	while (1)
	{
    
		val1 = GPFDAT;
		val2 = GPGDAT;

		if (val1 & (1<<0)) /* s2 --> gpf6 */
		{
    
			/*  Release  */
			GPFDAT |= (1<<6);
		}
		else
		{
    
			/*  Press down  */
			GPFDAT &= ~(1<<6);
		}

		if (val1 & (1<<2)) /* s3 --> gpf5 */
		{
    
			/*  Release  */
			GPFDAT |= (1<<5);
		}
		else
		{
    
			/*  Press down  */
			GPFDAT &= ~(1<<5);
		}

		if (val2 & (1<<3)) /* s4 --> gpf4 */
		{
    
			/*  Release  */
			GPFDAT |= (1<<4);
		}
		else
		{
    
			/*  Press down  */
			GPFDAT &= ~(1<<4);
		}

		
	}

	return 0;
}