S3C2440之UART驱动代码模板（RealView MDK）

好记心不如烂笔头，为方便以后查看代码及代码重复利用，这里贴出S3C2440 UART驱动代码。使用友善MINI2440开发板，开发环境为RealView MDK 4.22。需要注意的是，本代码中，对GPIO的初始化放在了s3c2440.s中完成，采用keil自带的html方式进行配置。

该源码结构简单明了，原始工程下载地址：点击打开链接

UART控制器初始化：

void Uart_Init(void)
{
#define rULCON0			(*(volatile unsigned int*)0x50000000)
#define rUCON0			(*(volatile unsigned int*)0x50000004)
#define rUBRDIV0		(*(volatile unsigned int*)0x50000028)

#define PCLK			50000000
#define BUADRATE		115200

	rULCON0 = 0x03;		//No parity, One stop bit, 8-bits data
	rUCON0	= 0x05;		//Tx Enable, Rx Enable, PCLK as source clock
	rUBRDIV0 = (int)(PCLK / (BUADRATE * 16)) - 1;	//115200bps
}

字符发送函数：

void Uart_Putc(unsigned char c)
{
#define rUTRSTAT0		(*(volatile unsigned int*)0x50000010)
#define rUTXH0			(*(volatile unsigned int*)0x50000020)

#define BUFFER_EMPTY	(1 << 1)

	while(!(rUTRSTAT0 & BUFFER_EMPTY));
	rUTXH0 = c;
}

字符接收函数：

unsigned char Uart_Getc(void)
{
#define rUTRSTAT0		(*(volatile unsigned int*)0x50000010)
#define rURXH0			(*(volatile unsigned int*)0x50000024)

#define BUFFER_READY	(1 << 0)

	while(!(rUTRSTAT0 & BUFFER_READY));
	return rURXH0;
}

为了使用printf库函数，需要进行如下重映射：

struct __FILE
{
int handle;
/* Whatever you require here. If the only file you are using is */
/* standard output using printf() for debugging, no file handling */
/* is required. */
};  

/* FILE is typedef'd in stdio.h. */
FILE __stdout;  

int fputc(int ch, FILE *f)
{
    Uart_Putc(ch); 

    return ch;
} 

int ferror(FILE *f) {
  /* Your implementation of ferror */
  return EOF;
}

测试代码：

int main(void)
{
	unsigned char ch;

	//clock_init();
	Uart_Init();
	printf("%s, %d", __FILE__, __LINE__);
	while(1)
	{
		ch = Uart_Getc();
		Uart_Putc(ch);
	}
}