uart.c

/*! \file uart.c \brief UART driver for ARM LPC2000 16550. */
//*****************************************************************************
//
// File Name    : 'uart.c'
// Title        : UART driver for ARM LPC2000 16550
// Author       : Pascal Stang - Copyright (C) 2004
// Created      : 4/2/2004
// Revised      : 4/2/2004
// Version      : 0.1
// Target MCU   : Philips ARM LPC2000 Series
// Editor Tabs  : 4
//
// Thanks to Bill Knight for providing the excellent processor/uart
//  #defines used in this driver.
// 
// This code is distributed under the GNU Public License
//      which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

#include <limits.h>
#include "LPC2000.h"

#include "global.h"
#include "uart.h"

//! enable and initialize the uart
void uart0Init(uint16_t baud, uint8_t mode, uint8_t fifomode)
{
    // set pin-select register to connect to UART0
    PINSEL0 = (PINSEL0 & ~U0_PINMASK) | U0_PINSEL;
    // reset and initialize the UART
    U0IER = 0;      // disable all interrupt sources
    U0IIR;          // clear any pending interrupts
    U0FCR = (UFCR_TX_FIFO_RESET|UFCR_RX_FIFO_RESET);    // reset the Tx/Rx FIFOs
    // set the baudrate divisor
    U0LCR = ULCR_DLAB_ENABLE;   // set divisor access bit (permits modification of divisors)
    U0DLL = (baud);             // set the baud division
    U0DLM = (baud>>8);
    U0LCR = 0;                  // reset DLAB (normal operation)
    // set line parameters and fifo mode
    U0LCR = mode;
    U0FCR = fifomode;
    // with uart configured, clear line status and receive registers
    U0RBR; U0LSR;
}

void uart1Init(uint16_t baud, uint8_t mode, uint8_t fifomode)
{
    // set pin-select register to connect to UART1
    PINSEL0 = (PINSEL0 & ~U1_PINMASK) | U1_PINSEL;
    // reset and initialize the UART
    U1IER = 0;      // disable all interrupt sources
    U1IIR;          // clear any pending interrupts
    U1FCR = (UFCR_TX_FIFO_RESET|UFCR_RX_FIFO_RESET);    // reset the Tx/Rx FIFOs
    // set the baudrate divisor
    U1LCR = ULCR_DLAB_ENABLE;   // set divisor access bit (permits modification of divisors)
    U1DLL = (baud);             // set the baud division
    U1DLM = (baud>>8);
    U1LCR = 0;                  // reset DLAB (normal operation)
    // set line parameters and fifo mode
    U1LCR = mode;
    U1FCR = fifomode;
    // with uart configured, clear line status and receive registers
    U1RBR; U1LSR;
}

int uart0SendByte(int data)
{
    // wait for tx buffer ready
    while( !(U0LSR & ULSR_THRE) );
    // send the character
    return (U0THR = data);
}

int uart1SendByte(int data)
{
    // wait for tx buffer ready
    while( !(U1LSR & ULSR_THRE) );
    // send the character
    return (U1THR = data);
}

int uart0GetByte(void)
{
    // if character is available, return it
    if(U0LSR & ULSR_RDR)
        return (U0RBR);
    // otherwise, return failure
    return -1;
}

int uart1GetByte(void)
{   
    // if character is available, return it
    if(U1LSR & ULSR_RDR)
        return (U1RBR);
    // otherwise, return failure
    return -1;
}

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