uart.c

ADS1241与MSP430F449接口设计

/*****************************************************************************
**	[File]
**	uart1.c
** 	[Purpose]
**	UART routines
**	[Changes]
**	
*/
#include "hpa449lib.h"
#include <signal.h>

#ifdef __BUFFERED_SERIAL
#define TX_BUFSIZE	100
static volatile unsigned char TXBuffer[TX_BUFSIZE];
static volatile int ReadPointer;
static volatile int WritePointer;
unsigned volatile char nTXItems;
unsigned volatile char fTXBufFree;
#endif

void UART1_Init(unsigned int BaudRateDivider, unsigned char Modulator)
{
	UCTL1 = SWRST;
	
#ifdef __BUFFERED_SERIAL
	ReadPointer = WritePointer = 0;
	nTXItems = 0;
	fTXBufFree = 1;
#endif	

	UTCTL1 = SSEL1;                 // UCLK = SMCLK
	
	UBR01 = BaudRateDivider & 0xff; // baud rate
	UBR11 = (BaudRateDivider >> 8) & 0xff;  
	UMCTL1 = Modulator;             // modulation
	
	UCTL1 = CHAR | SWRST;           // 8-bit character *SWRST*
	ME2 |= (UTXE1) + (URXE1);       // Enable USART0 TXD/RXD
	P4SEL |= 0x03;                  // P4.1,0 = USART0 TXD/RXD
	P4DIR |= 0x01;          	// P4.0 output direction
	UCTL1 &= ~SWRST;
#ifdef __BUFFERED_SERIAL
	IE2 |=  UTXIE1;	// Enable USART0 TX interrupt
#endif	
}

void UART1_EnableReceiveInterrupt(int fEnable)
{
	if (fEnable)
		IE2 |=  URXIE1;	// Enable USART1 RX interrupt
	else
		IE2 &= ~URXIE1;
}

void UART1_EnableTransmitInterrupt(int fEnable)
{
	if (fEnable)
		IE2 |=  UTXIE1;	// Enable USART1 TX interrupt
	else
		IE2 &= ~UTXIE1;
}

#ifdef __BUFFERED_SERIAL
int SendString(char * pData)
{
	int fSuccess = 1;
	while (*pData)
	{
	   fSuccess &= SendByte(*pData++);
	}
	return fSuccess;
}

int SendBytes(unsigned char * pData, unsigned char nBytes)
{
	int fSuccess = 1;
	while (nBytes--)
	{
		fSuccess &= SendByte(*pData++);
	}
	return fSuccess;
}

int SendByte(unsigned char Byte2Send)
{
	int fSuccess = 1;
	
	// don't mess with the buffer with interrupts enabled
	// ???? GH possible problem if TXInt was not enabled before
	IE2 &= ~UTXIE1;
	// if TXBUF is empty, send direct, else buffer
	if ((nTXItems == 0) && fTXBufFree)
	{
		TXBUF1 = Byte2Send;
		fTXBufFree = 0;
	}
	else
	{
      // wait until another byte is available
      while (nTXItems == TX_BUFSIZE)
      {
         IE2 |=  UTXIE1;
      	IE2 &= ~UTXIE1;
      }
      nTXItems++;
      TXBuffer[WritePointer++] = Byte2Send;
      if (WritePointer == TX_BUFSIZE)
         WritePointer = 0;
   }
	IE2 |=  UTXIE1;
	return fSuccess;
}


interrupt (USART1TX_VECTOR) UART1TXIntRoutine(void)
{
	// if we have more items to send, do so
	if (nTXItems > 0)
	{
		nTXItems--;
		TXBUF1 = TXBuffer[ReadPointer++];
		if (ReadPointer == TX_BUFSIZE)
		{
			ReadPointer = 0;
		}
	}
	else
	{
		// mark the transmitter free
		fTXBufFree = 1;
	}
}

#endif