uart.c

LPC1114_例程和教程

/*****************************************************************************
 *   uart.c:  UART API file for NXP LPC13xx Family Microprocessors
 *
 *   Copyright(C) 2008, NXP Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2008.08.21  ver 1.00    Preliminary version, first Release
 *
******************************************************************************/
#include "LPC11xx.h"
#include "uart.h"

volatile uint32_t UARTStatus;
volatile uint8_t  UARTTxEmpty = 1;
volatile uint8_t  UARTBuffer[BUFSIZE];
volatile uint32_t UARTCount = 0;



/*****************************************************************************
** Function name:		UART_IRQHandler
**
** Descriptions:		UART interrupt handler
**
** parameters:			None
** Returned value:		None
** 
*****************************************************************************/
void UART_IRQHandler(void)
{
  uint8_t IIRValue, LSRValue;
  uint8_t Dummy = Dummy;

  IIRValue = LPC_UART->IIR;
    
  IIRValue >>= 1;			/* skip pending bit in IIR */
  IIRValue &= 0x07;			/* check bit 1~3, interrupt identification */
  if (IIRValue == IIR_RLS)		/* Receive Line Status */
  {
    LSRValue = LPC_UART->LSR;
    /* 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 */
      UARTStatus = LSRValue;
      Dummy = LPC_UART->RBR;	/* Dummy read on RX to clear 
								interrupt, then bail out */
      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 */
      UARTBuffer[UARTCount++] = LPC_UART->RBR;
      if (UARTCount == BUFSIZE)
      {
        UARTCount = 0;		/* buffer overflow */
      }	
    }
  }
  else if (IIRValue == IIR_RDA)	/* Receive Data Available */
  {
    /* Receive Data Available */
    UARTBuffer[UARTCount++] = LPC_UART->RBR;
    if (UARTCount == BUFSIZE)
    {
      UARTCount = 0;		/* buffer overflow */
    }
  }
  else if (IIRValue == IIR_CTI)	/* Character timeout indicator */
  {
    /* Character Time-out indicator */
    UARTStatus |= 0x100;		/* Bit 9 as the CTI error */
  }
  else if (IIRValue == IIR_THRE)	/* THRE, transmit holding register empty */
  {
    /* THRE interrupt */
    LSRValue = LPC_UART->LSR;		/* Check status in the LSR to see if
								valid data in U0THR or not */
    if (LSRValue & LSR_THRE)
    {
      UARTTxEmpty = 1;
    }
    else
    {
      UARTTxEmpty = 0;
    }
  }
  return;
}

/*****************************************************************************
** Function name:		UARTInit
**
** Descriptions:		Initialize UART0 port, setup pin select,
**				clock, parity, stop bits, FIFO, etc.
**
** parameters:			UART baudrate
** Returned value:		None
** 
*****************************************************************************/
void UARTInit(void)
{
//  uint32_t Fdiv;
//  uint32_t regVal;

  UARTTxEmpty = 1;
  UARTCount = 0;
  
  NVIC_DisableIRQ(UART_IRQn);

  LPC_IOCON->PIO1_6 &= ~0x07;    /*  UART I/O config */
  LPC_IOCON->PIO1_6 |= 0x01;     /* UART RXD */
  LPC_IOCON->PIO1_7 &= ~0x07;	
  LPC_IOCON->PIO1_7 |= 0x01;     /* UART TXD */
  /* Enable UART clock */
  LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12);
  LPC_SYSCON->UARTCLKDIV = 0x1;     /* divided by 1 */

 // LPC_UART->LCR = 0x83;             /* 8 bits, no Parity, 1 Stop bit */
 // regVal = LPC_SYSCON->UARTCLKDIV;
 // Fdiv = (((SystemFrequency/LPC_SYSCON->SYSAHBCLKDIV)/regVal)/16)/baudrate ;	/*baud rate */

 // LPC_UART->DLM = Fdiv / 256;							
//  LPC_UART->DLL = Fdiv % 256;
//  LPC_UART->LCR = 0x03;		/* DLAB = 0 */
 // LPC_UART->FCR = 0x07;		/* Enable and reset TX and RX FIFO. */

  /* Read to clear the line status. */
 // regVal = LPC_UART->LSR;

  /* Ensure a clean start, no data in either TX or RX FIFO. */
 // while ( LPC_UART->LSR & (LSR_THRE|LSR_TEMT) != (LSR_THRE|LSR_TEMT) );
 // while ( LPC_UART->LSR & LSR_RDR )
//  {
//	regVal = LPC_UART->RBR;	/* Dump data from RX FIFO */
//  }
 
  /* Enable the UART Interrupt */
//  NVIC_EnableIRQ(UART_IRQn);

//#if TX_INTERRUPT
 // LPC_UART->IER = IER_RBR | IER_THRE | IER_RLS;	/* Enable UART interrupt */
//#else
 // LPC_UART->IER = IER_RBR | IER_RLS;	/* Enable UART interrupt */
//#endif
  return;
}

/*****************************************************************************
** 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( char *BufferPtr, uint32_t Length)
{
  
  while ( Length != 0 )
  {
	  /* THRE status, contain valid data */
#if !TX_INTERRUPT
	  while ( !(LPC_UART->LSR & LSR_THRE) );
	  LPC_UART->THR = *BufferPtr;
#else
	  /* Below flag is set inside the interrupt handler when THRE occurs. */
      while ( !(UARTTxEmpty & 0x01) );
	  LPC_UART->THR = *BufferPtr;
      UARTTxEmpty = 0;	/* not empty in the THR until it shifts out */
#endif
      BufferPtr++;
      Length--;
  }
  return;
}

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