uart.c

/*! \file uart.c \brief UART driver for AT91SAM7S. */
//*****************************************************************************
//
// File Name    : 'uart.c'
// Title        : UART driver for AT91SAM7S
// Author       : Pascal Stang - Copyright (C) 2004-2006
// Created      : 4/3/2004
// Revised      : 7/4/2006
// Version      : 0.1
// Target MCU   : Atmel ARM AT91SAM7S Series
// Editor Tabs  : 4
//
// This code is distributed under the GNU Public License
//      which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

// AT91SAM7S definitions
#include "at91sam7s64.h"
#include "global.h"

#include "uart.h"

// Global Pointer to USARTs
//AT91S_USART * pUSART0 = AT91C_BASE_US0;
//AT91S_USART * pUSART1 = AT91C_BASE_US1;
#define pUSART0  ((AT91S_USART*)AT91C_BASE_US0)
#define pUSART1  ((AT91S_USART*)AT91C_BASE_US1)
#define pUSART2  ((AT91S_USART*)AT91C_BASE_DBGU)

//! enable and initialize the uart
void uart0Init(uint16_t bauddiv, uint32_t mode)
{
    // enable the clock of UART0
    AT91C_BASE_PMC->PMC_PCER = (1<<AT91C_ID_US0);
    // enable uart pins on PIO
    *AT91C_PIOA_PDR = AT91C_PA5_RXD0 | AT91C_PA6_TXD0;
    // select peripheral connection
    *AT91C_PIOA_ASR = AT91C_PA5_RXD0 | AT91C_PA6_TXD0;
    // disable I/O pullup
     *AT91C_PIOA_PPUDR = AT91C_PA5_RXD0;
    // reset the UART
    pUSART2->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RXDIS |AT91C_US_TXDIS;
    // set serial line mode
    pUSART0->US_MR =    AT91C_US_USMODE_NORMAL |// Normal Mode
                        AT91C_US_CLKS_CLOCK |   // Clock = MCK
                        mode;                   // user-defined data parameters
    // set the baud rate
    pUSART0->US_BRGR = bauddiv;
    // enable the uart
    pUSART0->US_CR = AT91C_US_RXEN | AT91C_US_TXEN;
}

void uart1Init(uint16_t bauddiv, uint32_t mode)
{
    // enable the clock of UART1
    AT91C_BASE_PMC->PMC_PCER = (1<<AT91C_ID_US1);
    // enable uart pins on PIO
    *AT91C_PIOA_PDR = AT91C_PA21_RXD1 | AT91C_PA22_TXD1;
    // select peripheral connection
    *AT91C_PIOA_ASR = AT91C_PA21_RXD1 | AT91C_PA22_TXD1;
    // disable I/O pullup
    *AT91C_PIOA_PPUDR = AT91C_PA21_RXD1;
    // reset the UART
    pUSART2->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RXDIS |AT91C_US_TXDIS;
    // set serial line mode
    pUSART1->US_MR =    AT91C_US_USMODE_NORMAL |// Normal Mode
                        AT91C_US_CLKS_CLOCK |   // Clock = MCK
                        mode;                   // user-defined data parameters
    // set the baud rate
    pUSART1->US_BRGR = bauddiv;
    // enable the uart
    pUSART1->US_CR = AT91C_US_RXEN | AT91C_US_TXEN;
}

void uart2Init(uint16_t bauddiv, uint32_t mode)
{
    // enable the clock of DBGU
    AT91C_BASE_PMC->PMC_PCER = (1<<AT91C_ID_SYS);
    // enable uart pins on PIO
    *AT91C_PIOA_PDR = AT91C_PA9_DRXD | AT91C_PA10_DTXD;
    // reset the UART
    pUSART2->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RXDIS |AT91C_US_TXDIS;
    // set serial line mode
    pUSART2->US_MR =    AT91C_US_USMODE_NORMAL |    // Normal Mode
                        AT91C_US_CLKS_CLOCK |       // Clock = MCK
                        AT91C_US_CHRL_8_BITS |      // 8-bit Data (no effect on DBGU)
                        AT91C_US_PAR_NONE |         // No Parity
                        AT91C_US_NBSTOP_1_BIT;      // 1 Stop Bit (no effect on DBGU)
    // set the baud rate
    pUSART2->US_BRGR = bauddiv;
    // enable the uart
    pUSART2->US_CR = AT91C_US_RXEN | AT91C_US_TXEN;
}

int uart0SendByte(int data)
{
    // wait for tx buffer ready
    while( !(pUSART0->US_CSR & AT91C_US_TXRDY) );
    // send the character
    return (pUSART0->US_THR = data);
}

int uart1SendByte(int data)
{
    // wait for tx buffer ready
    while( !(pUSART1->US_CSR & AT91C_US_TXRDY) );
    // send the character
    return (pUSART1->US_THR = data);
}

int uart2SendByte(int data)
{
    // wait for tx buffer ready
    while( !(pUSART2->US_CSR & AT91C_US_TXRDY) );
    // send the character
    return (pUSART2->US_THR = data);
}

int uart0GetByte(void)
{   
    // if character is available, return it
    if(pUSART0->US_CSR & AT91C_US_RXRDY)
        return (pUSART0->US_RHR);
    // otherwise, return failure
    return -1;
}

int uart1GetByte(void)
{   
    // if character is available, return it
    if(pUSART1->US_CSR & AT91C_US_RXRDY)
        return (pUSART1->US_RHR);
    // otherwise, return failure
    return -1;
}

int uart2GetByte(void)
{
    // if character is available, return it
    if(pUSART2->US_CSR & AT91C_US_RXRDY)
        return (pUSART2->US_RHR);
    // otherwise, return failure
    return -1;
}

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