ch4_uart_int.c

通用异步同步串行通信UART方式的基于atmega128l的实现

#include<avr/io.h>
#include<avr/interrupt.h>
#include<avr/signal.h>

#define uchar unsigned char
#define uint unsigned int

uchar g_bTxdPos = 0; //发送定位计数器
uchar g_bTxdLen = 0; //等待发送字节数
uchar g_bRxdPos = 0; //接收定位计数器
uchar g_bRxdLen = 0; //等待接收字节数

uchar g_aSendBuff[16]; //发送数据缓冲区
uchar g_aRecvBuff[16];  //接收数据缓冲区

//接收中断
SIGNAL(SIG_UART1_RECV)
{
	uchar c = UDR0 ;
	if(g_bRxdLen>0)
		{
			g_aRecvBuff[g_bRxdPos] = c;
			g_bRxdLen--;
		}
}


//发送中断
SIGNAL(SIG_UART0_TRANS)
{
	if(--g_bTxdLen>0)
		{
			UDR0 = g_aSendBuff[++g_bRxdPos];
		}
}


//receive complete or not
uchar IsRecvComplete(void)
{
	return g_bTxdLen == 0;
	
}


void SendToUart(uchar size)
{
	g_bRxdPos = 0;
	g_bTxdLen = size;
	UDR0 = g_aSendBuff[0];
	while(g_bTxdLen>0);
}


//接收指定长度数据到接收缓冲区
void RecvFromUart(uchar size, uchar bwait)
{
	g_bTxdPos = 0;
	g_bRxdLen = size;
	if(bwait)
		{
			while(g_bRxdLen>0)
				;// empty body
		}//end if
}

int main()
{
	uchar i;

	//uart inintilization
	//enable receive transmit and interrupt
	UCSR0B = (1<<RXCIE0) | (1<<TXCIE0) | (1<<RXEN0) | (1<<TXEN0);
	UBRR0L = 51; //baud = 9600

	sei(); //always permit interrupt

	while(1)
	{
		//asyno receive 16 byte data
		RecvFromUart(16,0);

		//copy the data into the buffer of send
		for(i=0;i<16;i++)
			{
				g_aSendBuff[i] = g_aRecvBuff[i];
			}

		SendToUart(16);
	}
}