//串口中斷服務程序，僅需做簡單調用即可完成串口輸入輸出的處理
//出入均設有緩沖區，大小可任意設置。
//*************************************************************************
#include "c8051f020.h"				// SFR declarations
#include "intrins.h"

#define	BAUDRATE0		115200		// 用戶定義的UART0 波特率

#define DB_SENDMAXSIZE 0xf0
#define DB_RECMAXSIZE 0xf0

bit CommRecDataOverflowFlag,FlagRecComm,SendItComm;
extern unsigned char Count1ms;
unsigned char CommSendBufferHead, CommSendBufferTail;
unsigned char xdata CommSendBuffer[DB_SENDMAXSIZE]; 
unsigned char CommRecBufferHead, CommRecBufferTail;
unsigned char xdata CommRecBuffer[DB_RECMAXSIZE]; 

void ClearCommRecBuffer(void)
{
	unsigned char i;
	CommRecBufferHead=CommRecBufferTail=0;
	CommSendBufferHead=CommSendBufferTail=0;
	FlagRecComm=0;
	for (i=0;i<DB_SENDMAXSIZE;i++)
	{
		CommSendBuffer[i]=0;
	}
	for (i=0;i<DB_RECMAXSIZE;i++)
	{
		CommRecBuffer[i]=0;
	}

}
void OpenComm(void) 
{
	PCON |= 0x80;		// SMOD=1 (HW_UART uses Timer 1 overflow with no divide down).
	TMOD |= 0x20;		// Configure Timer 1 for use by UART0
	CKCON |= 0x10;		// Timer 1 derived from SYSCLK

	RCAP2H=(65536-(SYSCLK/BAUDRATE0/32))/256;
	RCAP2L=(65536-(SYSCLK/BAUDRATE0/32))%256;
	TH2=RCAP2H;TL2=RCAP2L;
	CT2=0;				//T2:timer mode	
	TR2=1;
	TCLK=1;RCLK=1;		//說明:52,對于SIO0,可選擇T1(TCLK=0,RCLK=0)或T2(TCLK=1,RCLK=1)作為波特率發生器
					    //            SIO1只能用T1作為波特率發生器
					    //baud=OSC/(32*(65536-[RCAP2H,RCAP2L])
	CommSendBufferHead=CommSendBufferTail=0; // set the head and tail to the base of the ring buffer
	CommRecBufferHead=CommRecBufferTail=0;
	FlagRecComm=0;
	RI0=0;					// Clear HW_UART receive and transmit
	TI0=0;					// complete indicators.
	SCON0 = 0x50;			// Configure UART0 for mode 1, receiver enabled.
	ES0=1; 					// allow the serial interrupt
//	PS=1;
	SendItComm=1;
}
void SendCommChar(char ch)
{
	CommSendBuffer[CommSendBufferTail]=ch; 
	CommSendBufferTail++;
	if (CommSendBufferTail==DB_SENDMAXSIZE)
	{ 	
		CommSendBufferTail=0;
	}
	if (SendItComm)
	{	 
		SendItComm=0;
		SBUF0=CommSendBuffer[CommSendBufferHead]; 
	}
	while (CommSendBufferHead!=CommSendBufferTail);
	return ;
}
code unsigned char hex[]="0123456789ABCDEF";
void SendCommHex(unsigned char senddata)//往串口發送hex碼 表示的一個字符 例如senddata=0x3A那么將向串口發送兩個字符'3','A'hex[]為轉換表，在前面有定義
{
	unsigned char ch;
	ch=senddata>>4;
	SendCommChar(hex[ch]);
	ch=senddata&0x0F;
	SendCommChar(hex[ch]);
}
void SendCommWord(unsigned int asciiword)
//向串口發送一個int型的 hex碼表示的字符 例如：asciiword=0x124D 將向串口發送4個字符：'1','2','4','D'
{
	unsigned char ascii;
	ascii=asciiword>>8;
	SendCommHex(ascii);
	ascii=asciiword&0xff;
	SendCommHex(ascii);
}

void SendCommLong(unsigned long asciilong)
{
	SendCommWord(asciilong>>16);
	SendCommWord(asciilong&0xffff);
}

void SendCommString(unsigned char *base) 
{
unsigned char i=0;
	if (base[0]==0) return;
	for (;;)
	{	
		if (base[i]==0) break;
		CommSendBuffer[CommSendBufferTail]=base[i]; 
		CommSendBufferTail++; 
		if (CommSendBufferTail==DB_SENDMAXSIZE)
		{ 						
			CommSendBufferTail=0;
		}
		i++;
	}
	if (SendItComm)
	{	 						
		SendItComm=0;
		SBUF0=CommSendBuffer[CommSendBufferHead];
	}
	while (CommSendBufferHead!=CommSendBufferTail);
}

void CommISR(void) interrupt 4
{
	if (_testbit_(TI0))
	{
		TI0=0;
		CommSendBufferHead++; 	
		if (CommSendBufferHead==DB_SENDMAXSIZE)
		{	 
			CommSendBufferHead=0;
		}
		if (CommSendBufferHead!=CommSendBufferTail)
		{	 
			SBUF0=CommSendBuffer[CommSendBufferHead]; // send the next byte
			SendItComm=0;
		}
		else
		{
			SendItComm=1;
		}
	}
	if (_testbit_(RI0))	
	{	 
		RI0=0;
		if (CommRecBufferTail==CommRecBufferHead)
		{
			CommRecDataOverflowFlag=1;				//接收緩沖區溢出
		}
		CommRecBuffer[CommRecBufferTail]=SBUF0;     //receive data           
	    CommRecBufferTail++;
	    if (CommRecBufferTail==DB_RECMAXSIZE)
	    {
	    	CommRecBufferTail=0;
	    }
		FlagRecComm=1;
   	}
}

//從接收緩沖區讀數據 ,無數據返回0,有數據返回1
bit GetCommChar(unsigned char idata *ch)      
{ 
	if (CommRecBufferTail==CommRecBufferHead) return 0;     
	*ch=CommRecBuffer[CommRecBufferHead];
	CommRecBufferHead++;
	if (CommRecBufferHead==DB_RECMAXSIZE)
	{
		CommRecBufferHead=0;
	}
	if (CommRecBufferTail==CommRecBufferHead) FlagRecComm=0;
	return 1;
}