uart.c

lpc2148-keil环境下的各个功能模块的例程

/*****************************************************************************
 *   uart.c:  UART API file for Philips LPC214x Family Microprocessors
 *
 *   Copyright(C) 2006, Philips Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2005.10.01  ver 1.00    Prelimnary version, first Release
 *
******************************************************************************/
#include "LPC214x.H"                        /* LPC21xx definitions */
#include "type.h"
#include "target.h"
#include "irq.h"
#include "uart.h"

DWORD UART0Status;
BYTE UART0TxEmpty = 1;
BYTE UART0Buffer[BUFSIZE];
DWORD UART0Count = 0;

/*****************************************************************************
** Function name:		UART0Handler
**
** Descriptions:		UART0 interrupt handler
**
** parameters:			None
** Returned value:		None
** 
*****************************************************************************/
void UART0Handler (void) __irq 
{
    BYTE IIRValue, LSRValue;
    BYTE Dummy;

    IENABLE;				/* handles nested interrupt */	
    IIRValue = U0IIR;
    
    IIRValue >>= 1;			/* skip pending bit in IIR */
    IIRValue &= 0x07;			/* check bit 1~3, interrupt identification */
    if ( IIRValue == IIR_RLS )		/* Receive Line Status */
    {
	LSRValue = U0LSR;
	/* Receive Line Status */
	if ( LSRValue & (LSR_OE|LSR_PE|LSR_FE|LSR_RXFE|LSR_BI) )
	{
	    /* There are errors or break interrupt */
	    /* Read LSR will clear the interrupt */
	    UART0Status = LSRValue;
	    Dummy = U0RBR;		/* Dummy read on RX to clear 
					interrupt, then bail out */
	    IDISABLE;
	    VICVectAddr = 0;		/* Acknowledge Interrupt */
	    return;
	}
	if ( LSRValue & LSR_RDR )	/* Receive Data Ready */			
	{
	    /* If no error on RLS, normal ready, save into the data buffer. */
	    /* Note: read RBR will clear the interrupt */
	    UART0Buffer[UART0Count] = U0RBR;
	    UART0Count++;
	    if ( UART0Count == BUFSIZE )
	    {
		UART0Count = 0;		/* buffer overflow */
	    }	
	}
    }
    else if ( IIRValue == IIR_RDA )	/* Receive Data Available */
    {
	/* Receive Data Available */
	UART0Buffer[UART0Count] = U0RBR;
	UART0Count++;
	if ( UART0Count == BUFSIZE )
	{
	    UART0Count = 0;		/* buffer overflow */
	}
    }
    else if ( IIRValue == IIR_CTI )	/* Character timeout indicator */
    {
	/* Character Time-out indicator */
	UART0Status |= 0x100;		/* Bit 9 as the CTI error */
    }
    else if ( IIRValue == IIR_THRE )	/* THRE, transmit holding register empty */
    {
	/* THRE interrupt */
	LSRValue = U0LSR;		/* Check status in the LSR to see if
					valid data in U0THR or not */
	if ( LSRValue & LSR_THRE )
	{
	    UART0TxEmpty = 1;
	}
	else
	{
	    UART0TxEmpty = 0;
	}
    }
    
    IDISABLE;
    VICVectAddr = 0;		/* Acknowledge Interrupt */
}

/*****************************************************************************
** Function name:		UARTInit
**
** Descriptions:		Initialize UART0 port, setup pin select,
**				clock, parity, stop bits, FIFO, etc.
**
** parameters:			UART baudrate
** Returned value:		true or false, return false only if the 
**				interrupt handler can't be installed to the 
**				VIC table
** 
*****************************************************************************/
DWORD UARTInit( DWORD baudrate )
{
    DWORD Fdiv;

    PINSEL0 = 0x00050005;       /* Enable RxD1 and TxD1, RxD0 and TxD0 */

    U0LCR = 0x83;               /* 8 bits, no Parity, 1 Stop bit    */
    Fdiv = ( Fpclk / 16 ) / baudrate ;	/*baud rate */
    U0DLM = Fdiv / 256;							
    U0DLL = Fdiv % 256;	
    U0LCR = 0x03;               /* DLAB = 0                         */
    U0FCR = 0x07;		/* Enable and reset TX and RX FIFO. */

    if ( install_irq( UART0_INT, (void *)UART0Handler ) == FALSE )
    {
	return (FALSE);
    }
   
    U0IER = IER_RBR | IER_THRE | IER_RLS;	/* Enable UART0 interrupt */
    return (TRUE);
}

/*****************************************************************************
** Function name:		UARTSend
**
** Descriptions:		Send a block of data to the UART 0 port based
**				on the data length
**
** parameters:			buffer pointer, and data length
** Returned value:		None
** 
*****************************************************************************/
void UARTSend(BYTE *BufferPtr, DWORD Length )
{
    while ( Length != 0 )
    {
	while ( !(UART0TxEmpty & 0x01) );	/* THRE status, contain valid 
						data */
	U0THR = *BufferPtr;
	UART0TxEmpty = 0;	/* not empty in the THR until it shifts out */
	BufferPtr++;
	Length--;
    }
    return;
}

/******************************************************************************
**                            End Of File
******************************************************************************/