softuart.c

用软件实现的异步串行口源程序代码 用软件实现的异步串行口源程序代码

//------------------------------------------------------------------------------------
//
// Copyright 2001	Cygnal Integrated Products, Inc.
//
// FILE NAME		: SoftUart.c
// TARGET DEVICE	: C8051F02x
// Modify ON		: 01/10/02
// Modify BY		: WWW.XHL.COM.CN
//
// Software UART program, using PCA as baud rate source.
// PCA module 4 is used as receive baud rate source and START detector.  For START
// detection, module 4 is configured in negative-edge capture mode.  For all other
// SW_UART operations, module 4 is configured as a software timer.  Module match
// interrupts are used to generate the baud rate.  Module 3 generates the transmit
// baud rate in software timer mode. 
// Code assumes an external crystal is attached between the XTAL1 and XTAL2 pins.
// The frequency of the external crystal should be defined in the SYSCLK constant.
// 
// INITIALIZATION PROCEDURE:
// 1) Define SYSCLK according to external crystal frequency.
// 2) Define desired BAUD_RATE.
// 3) Call SW_UART_INIT().
// 4) Set SREN to enable SW_UART receiver.
// 5) Set SES only if user-level interrupt support is desired.
// 6) Call SW_UART_ENABLE().
//
// TO TRANSMIT:
// 1) Poll STXBSY for zero.
// 2) Write data to TDR.
// 3) Set CCF1 to initiate transmit.
// 4) STI will be set upon transmit completion.  An IE7 interrupt is generated if 
//    user-level interrupts are enabled.
//
// TO RECEIVE:
// 1) If in polled mode, poll SRI.  If in interrupt mode, check SRI in IE7 Interrupt
//    Service Routine.
// 2) Read data from RDR.
// 
// P1.2 ->  CEX0 (SW_UART0 TX)
// P1.3 ->  CEX1 (SW_UART0 RX)
// P1.4 ->  CEX0 (SW_UART1 TX)
// P1.5 ->  CEX1 (SW_UART1 RX)

//

/*  端口配置
	XBR0 = 0x27;	// XBAR0: Initial Reset Value
	XBR1 = 0x00;	// XBAR1: Initial Reset Value
	XBR2 = 0x44;	// XBAR2: Initial Reset Value
    P0MDOUT = 0x1D; // Output configuration for P0 
    P1MDOUT = 0x01; // Output configuration for P1 
		// P0.0 = UART TX0        (Push-Pull Output)
		// P0.1 = UART RX0        (Open-Drain Output/Input)
		// P0.2 = SPI Bus SCK     (Push-Pull Output)
		// P0.3 = SPI Bus MISO    (Push-Pull Output)
		// P0.4 = SPI Bus MOSI    (Push-Pull Output)
		// P0.5 = SPI Bus NSS     (Open-Drain Output/Input)
		// P0.6 = SMBus SDA       (Open-Drain Output/Input)
		// P0.7 = SMBus SCL       (Open-Drain Output/Input)


		// Port 1

		// P1.0 = UART TX1        (Push-Pull Output)
		// P1.1 = UART RX1        (Open-Drain Output/Input)
		// P1.2 = PCA CEX0        (Push-Pull Output)
		// P1.3 = PCA CEX1        (Push-Pull Output)
		// P1.4 = PCA CEX2        (Push-Pull Output)
		// P1.5 = PCA CEX3        (Push-Pull Output)
		// P1.6 = GP I/O          (Open-Drain Output/Input)
		// P1.7 = GP I/O          (Open-Drain Output/Input)
*/ 
//-----------------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------------

#include "TestSerial.h"

#define	BAUDRATE2		19200		// 用户定义的SW_UART 波特率
#define	UART2_TIMER		SYSCLK/BAUDRATE2/4	//对应一个位时间的PCA 计数值(PCA 配置为对SYSCLK/4 计数)
#define	UART2_STARTTIME	UART2_TIMER*3/2		// 3/2 位时间用于接收到一个起始位后在起始位边沿之后RX 
											//应在一个位时间内保持低电平第一个位采样在下一个位时间的中间开始

#define	BAUDRATE3		19200		
#define	UART3_TIMER		SYSCLK/BAUDRATE3/4	
#define	UART3_STARTTIME	UART3_TIMER*3/2		
											


#define NULL ((void *) 0L)
#define DB_SENDMAXSIZE2 0xf0
#define DB_RECMAXSIZE2 0xf0

#define DB_SENDMAXSIZE3 0xf0
#define DB_RECMAXSIZE3 0xf0

bit FlagRecComm2,SendItComm2;
unsigned char CommSendBufferHead2, CommSendBufferTail2;
unsigned char xdata CommSendBuffer2[DB_SENDMAXSIZE2]; 
unsigned char CommRecBufferHead2, CommRecBufferTail2;
unsigned char xdata CommRecBuffer2[DB_RECMAXSIZE2]; 

bit FlagRecComm3,SendItComm3;
unsigned char CommSendBufferHead3, CommSendBufferTail3;
unsigned char xdata CommSendBuffer3[DB_SENDMAXSIZE3]; 
unsigned char CommRecBufferHead3, CommRecBufferTail3;
unsigned char xdata CommRecBuffer3[DB_RECMAXSIZE3]; 


//-----------------------------------------------------------------------------------
//Global VARIABLES
//-----------------------------------------------------------------------------------
bit	SRI0;					// SW_UART Receive Complete Indicator
bit	STI0;					// SW_UART Transmit Complete Indicator
bit	STXBSY0;				// SW_UART TX Busy flag
bit SREN0;					// SW_UART RX Enable
bit	SES0;					// SW_UART User-level Interrupt Support Enable
sbit SW_RX0 = P1^3;  		// SW_UART Receive pin
sbit SW_TX0 = P1^2;  		// SW_UART Transmit pin
char TDR0;					// SW_UART TX Data Register
char RDR0;					// SW_UART RX Data Register (latch)

bit	SRI1;					// SW_UART Receive Complete Indicator
bit	STI1;					// SW_UART Transmit Complete Indicator
bit	STXBSY1;				// SW_UART TX Busy flag
bit SREN1;					// SW_UART RX Enable
bit	SES1;					// SW_UART User-level Interrupt Support Enable
sbit SW_RX1 = P1^5;  		// SW_UART Receive pin
sbit SW_TX1 = P1^4;  		// SW_UART Transmit pin
char TDR1;					// SW_UART TX Data Register
char RDR1;					// SW_UART RX Data Register (latch)

//------------------------------------------------------------------------------------
// Function PROTOTYPES
//------------------------------------------------------------------------------------

void	SW_UART_INIT0();			// SW_UART initialization routine
void	SW_UART_ENABLE0();			// SW_UART enable routine
void	PCA_ISR();					// SW_UART interrupt service routine
void 	USER_ISR0(void);			// SW_UART test interrupt service routine
void	SW_UART_INIT1();			// SW_UART initialization routine
void	SW_UART_ENABLE1();			// SW_UART enable routine
void 	USER_ISR1(void);			// SW_UART test interrupt service routine



void ClearCommRecBuffer2(void)
{
	CommRecBufferHead2=CommRecBufferTail2=0;
	FlagRecComm2=0;
}

void SendCommChar2(char ch)			//发送一字节
{
	CommSendBuffer2[CommSendBufferTail2]=ch;   // 将欲发送的字节存入发送缓冲区
	CommSendBufferTail2++; 					   // 移动发送缓冲区队列指针
	if (CommSendBufferTail2==DB_SENDMAXSIZE2)  // 检查循环队列指针
	{ 	
		CommSendBufferTail2=0;				   	
	}
	if (SendItComm2)						   // 空闲状态启动发送
	{	 
		STXBSY0 = 1; 						   // 发送标志置位
       	TDR0 = CommSendBuffer2[CommSendBufferHead2]; 
		CCF0 = 1;							   // 强制PCA模块0中断,启动发送
	}
	return ;
}

void SendCommBuffer2(unsigned char *base, unsigned char size)  //发送多字节
{
unsigned char i=0;
	if (!size) return; 			// 发送字节为空
	while (i<size) 				// 将发送的数据存入发送缓冲区,注意缓冲区的大小,本例程未考虑缓冲区溢出情况
	{	 
		CommSendBuffer2[CommSendBufferTail2]=base[i]; 
		i++;
		CommSendBufferTail2++; 
		if (CommSendBufferTail2==DB_SENDMAXSIZE2)
		{ 
			CommSendBufferTail2=0;
		}
	}
	if (SendItComm2)
	{
		STXBSY0 = 1; 
       	TDR0 = CommSendBuffer2[CommSendBufferHead2]; 
		CCF0 = 1;	
	}
}

bit GetCommChar2(unsigned char idata *ch)    //读取一字节数据,  有数据返回1,无数据返回0.
{ 
	if (CommRecBufferTail2==CommRecBufferHead2) return 0;     
	*ch=CommRecBuffer2[CommRecBufferHead2];
	CommRecBufferHead2++;
	if (CommRecBufferHead2==DB_RECMAXSIZE2)
	{
		CommRecBufferHead2=0;
	}
	if (CommRecBufferTail2==CommRecBufferHead2) FlagRecComm2=0;
	return 1;
}

//------------------------------------------------------------------------------------------
// SW_UART_INIT: 软件UART 初始化程序
// - 配置PCA: 模块1 设置为下跳沿捕捉方式; 模块0 设置为软件定时方式
//   PCA 时基 = 系统时钟/4; 关闭PCA中断 
//
void	SW_UART_INIT0(void)
{
	PCA0CPM1 = 0x10;		// Module 1 in negative capture mode; module 1 interrupt disabled.
	PCA0CPM0 = 0x48; 		// Module 0 in software timer mode; module  0 interrupt disabled.	
	PCA0CN = 0;				// Leave PCA disabled
	PCA0MD = 0x02;			// PCA timebase = SYSCLK/4; PCA counter
							// interrupt disabled.
	CCF1 = 0;				// Clear pending PCA module 0 and
	CCF0 = 0;				// module 1 capture/compare interrupts.
	SRI0 = 0;				// Clear Receive complete flag.
	STI0 = 0;				// Clear Transmit complete flag.
	SW_TX0 = 1;				// TX line initially high.	
	STXBSY0 = 0;				// Clear SW_UART Busy flag

	SREN0 = 1;				// Enable SW_UART Receiver
	SES0 = 1;				// User-level interrupt support enabled.
	SendItComm2=1;
}

//------------------------------------------------------------------------------------------
// SW_UART_ENABLE: SW_UART Enable Routine
// Enables SW_UART for use.
// - Enables PCA module 0 interrupts
// - Enables PCA module 1 interrupts
// - Starts PCA counter.
//
void	SW_UART_ENABLE0(void)
{
	PCA0CPM1 |= 0x01;		// Enable module 1 (receive) interrupts.
	PCA0CPM0 |= 0x01;		// Enable module 0 (transmit) interrupts.
	CR = 1;					// Start PCA counter.
	EIE1 |= 0x08;			// Enable PCA interrupts
	EA = 1;					// Globally enable interrupts
}

void ClearCommRecBuffer3(void)
{
	CommRecBufferHead3=CommRecBufferTail3=0;
	FlagRecComm3=0;
}

void SendCommChar3(char ch)			//发送一字节
{
	CommSendBuffer3[CommSendBufferTail3]=ch;   // 将欲发送的字节存入发送缓冲区
	CommSendBufferTail3++; 					   // 移动发送缓冲区队列指针
	if (CommSendBufferTail3==DB_SENDMAXSIZE3)  // 检查循环队列指针
	{ 	
		CommSendBufferTail3=0;				   	
	}
	if (SendItComm3)						   // 空闲状态启动发送
	{	 
		STXBSY1 = 1; 						   // 发送标志置位
       	TDR1 = CommSendBuffer3[CommSendBufferHead3]; 
		CCF2 = 1;							   // 强制PCA模块0中断,启动发送
	}
	return ;
}

void SendCommBuffer3(unsigned char *base, unsigned char size)  //发送多字节
{
unsigned char i=0;
	if (!size) return; 			// 发送字节为空
	while (i<size) 				// 将发送的数据存入发送缓冲区,注意缓冲区的大小,本例程未考虑缓冲区溢出情况
	{	 
		CommSendBuffer3[CommSendBufferTail3]=base[i]; 
		i++;
		CommSendBufferTail3++; 
		if (CommSendBufferTail3==DB_SENDMAXSIZE3)
		{ 
			CommSendBufferTail3=0;
		}
	}
	if (SendItComm3)
	{
		STXBSY1 = 1; 
       	TDR1 = CommSendBuffer2[CommSendBufferHead2]; 
		CCF2 = 1;	
	}
}

bit GetCommChar3(unsigned char idata *ch)    //读取一字节数据,  有数据返回1,无数据返回0.
{ 
	if (CommRecBufferTail3==CommRecBufferHead3) return 0;     
	*ch=CommRecBuffer3[CommRecBufferHead3];
	CommRecBufferHead3++;
	if (CommRecBufferHead3==DB_RECMAXSIZE2)
	{
		CommRecBufferHead3=0;
	}
	if (CommRecBufferTail3==CommRecBufferHead3) FlagRecComm3=0;
	return 1;
}



void	SW_UART_INIT1(void)
{
	PCA0CPM3 = 0x10;		// Module 1 in negative capture mode; module 1 interrupt disabled.
	PCA0CPM2 = 0x48; 		// Module 0 in software timer mode; module  0 interrupt disabled.	
	PCA0CN = 0;				// Leave PCA disabled
	PCA0MD = 0x02;			// PCA timebase = SYSCLK/4; PCA counter
							// interrupt disabled.
	CCF3 = 0;				// Clear pending PCA module 0 and
	CCF2 = 0;				// module 1 capture/compare interrupts.
	SRI1 = 0;				// Clear Receive complete flag.
	STI1 = 0;				// Clear Transmit complete flag.
	SW_TX1 = 1;				// TX line initially high.	
	STXBSY1 = 0;				// Clear SW_UART Busy flag

	SREN1 = 1;				// Enable SW_UART Receiver
	SES1 = 1;				// User-level interrupt support enabled.
	SendItComm3=1;
}

void	SW_UART_ENABLE1(void)
{
	PCA0CPM3 |= 0x01;		// Enable module 1 (receive) interrupts.
	PCA0CPM2 |= 0x01;		// Enable module 0 (transmit) interrupts.
	CR = 1;					// Start PCA counter.
	EIE1 |= 0x08;			// Enable PCA interrupts
	EA=1;
}

//------------------------------------------------------------------------------------
// Interrupt Service Routines
//------------------------------------------------------------------------------------
//
// PCA_ISR: PCA Interrupt Service Routine.
// This ISR is triggered by both transmit and receive functions, for each bit that