uart.c

老外的一个开源项目

// Copyright (c) David Vescovi.  All rights reserved.
// Part of Project DrumStix
// Windows Embedded Developers Interest Group (WE-DIG) community project.
// http://www.we-dig.org
// Copyright (c) Microsoft Corporation.  All rights reserved.
//------------------------------------------------------------------------------
//
//  File: uart.c
//
//------------------------------------------------------------------------------
#include <bsp.h>


static volatile UART_REG_T	*pUARTRegs;


//------------------------------------------------------------------------------
//
//  Function:   UARTInit
//
//  Initialize kitl serial port
//
//------------------------------------------------------------------------------
BOOL UARTInit(KITL_SERIAL_INFO *pInfo)
{
    BOOL rc = FALSE;
	
	pUARTRegs = (volatile UART_REG_T *)pInfo->pAddress;

	// Check if config paramters are supportable
	if (
		pInfo->baudRate < 9600 || pInfo->baudRate > 115200 ||
		pInfo->dataBits != 8 || pInfo->stopBits == 0 || pInfo->parity > 2
	) goto cleanUp;

    // Ensure that UART interrupts are turned off.
    //
    pUARTRegs->LCR     = 0x0;    // Clear DLAB.
    pUARTRegs->IER_DLH = 0x0;    // IER_DLH = 0x0.

    // Set the Baud Rate.
    // The divisor latches are at offsets 0 and 1, which are 
    // receive/transmit data and ier registers.
    //
    pUARTRegs->LCR         = 0x80;                // Access Divisor.
    pUARTRegs->THR_RBR_DLL = (14745600/pInfo->baudRate)/16; // Low byte divisor.
    pUARTRegs->IER_DLH     = 0x00;                // High byte divisor.
    pUARTRegs->LCR         = 0x0;                 // Clear DLAB.

    //Setting UART properties to 8N1 
    //
    pUARTRegs->LCR         = 0x3;     // 8 bits, 1 stop, no parity. Also LCR DLAB bit = 0.

    pUARTRegs->IIR_FCR     = 0x01;    // Enable the FIFO.
    pUARTRegs->IIR_FCR     = 0x07;    // Clear Rx,Tx FIFOs.

    // Don't enable UART interrupts - we'll poll for the data.
    //
    pUARTRegs->IER_DLH     = 0x0;  

    // Ensure loop-back test mode is off even though MCR reset value is 0x0. 
    //
    pUARTRegs->MCR         = 0x0;    // UART is in normal mode.
	//UART in auto handshake mode ... if it supports it

    // Enable the UART.
    //
    pUARTRegs->IER_DLH = 0x40;

	pInfo->bestSize = 1;       // read it one by one

	// Done
    rc = TRUE;
    
cleanUp:
    return rc;
}

//------------------------------------------------------------------------------
//
//  Function:  UARTSend
//
//------------------------------------------------------------------------------
UINT16 UARTSend(UINT8 *pData, UINT16 size)
{

    // This should not happen, but to be sure
    if (size == 0) return 0;

	// Spin if FIFO has more than half data.
    //
    while(!(pUARTRegs->LSR & UART_LSR_TDRQ));

	// Write a character byte to the FIFO.
    //
    pUARTRegs->THR_RBR_DLL = *pData;
    // We send only one char per call
	
	return 1;
}


//------------------------------------------------------------------------------
//
//  Function:  UARTFlowControl
//
//------------------------------------------------------------------------------
VOID UARTFlowControl(BOOL fOn)
{
	UINT32 uCtrl = (pUARTRegs->MCR & ~UART_MCR_RTS);

	pUARTRegs->MCR = (uCtrl | (fOn ? UART_MCR_RTS : 0));

	if (fOn) {
		// clear interrupts, if applicable
		uCtrl = pUARTRegs->IIR_FCR;
	}
}


//------------------------------------------------------------------------------
//
//  Function:  UARTRecv
//
//------------------------------------------------------------------------------
UINT16 UARTRecv(UINT8 *pData, UINT16 size)
{
    UINT32 lsr;
    UINT16 count = 0;

    count = 0;
	// Read LSR.
	lsr = pUARTRegs->LSR;
	if(lsr & UART_LSR_DR) {
		if (lsr & (UART_LSR_PE | UART_LSR_FE | UART_LSR_OE)) {
			KITL_RETAILMSG(ZONE_INIT, ("E\r\n"));
			pUARTRegs->IIR_FCR = (UART_FCR_RESETTF | UART_FCR_RESETRF | UART_FCR_TRFIFOE);
		} else {
			*pData = (UINT8)pUARTRegs->THR_RBR_DLL;
			count = 1;
		}
	}
	return count;
}

//------------------------------------------------------------------------------
//
//  Function:  UARTEnableInts
//
//------------------------------------------------------------------------------
void UARTEnableInts()
{
}

//------------------------------------------------------------------------------
//
//  Function:  UARTDisableInts
//
//------------------------------------------------------------------------------
void UARTDisableInts()
{
}

//------------------------------------------------------------------------------