uart.c

Jan 04, 2007 1. Add SPI support, see spi.h and spi.c 2. Add driver.h 3. Modified keyboard modu

/**
 * Copyright (c) 2006-2008 iWESUN (ShenZhen) Inf.
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE.
 *
 * This file is part of the AvrcX MTOS
 * 
 * Author: Winter Hu  <[e-mail]>
 * Create: Dec 25, 2006
 */

#include "uart.h"
#include "avrcx.h"

#if __UART__ == 1

NAKEDFIFO(rxbuf, UART_RXBUF_SIZE);
NAKEDFIFO(txbuf, UART_TXBUF_SIZE);
UARTCB uart = { UART_TX_EMPTY, NULL, &txbuf, &rxbuf};

/**
 * Initialize UART for Rx and Tx
 * You should invoke this method to initializ UART
 * Currently, this method just supported 8bit data, 1bit stop and none check
 *
 */
void init_uart(void){
  UBRRH = HI8(UART_UBRR);
  UBRRL = LO8(UART_UBRR);
  UCSRB = _BV(RXCIE) | _BV(TXCIE) | _BV(RXEN) | _BV(TXEN);
  UCSRC = 0x86; // Async, 8 bits data, 1 bit stop, None check
}

/**
 * Register user's hook to UART driver
 *
 * @param uart_hook, The hook to handle uart status
 */
void uart_set_hook(uart_hook hook){
  uart.hook = hook;
}

/**
 * Put a char to UART Tx queue
 *
 * @param char, the char need put to UART
 * @return 0 is successful, -1 is failed
 */
int uart_putchar(char b){
  int ret = 0;

  into_critical();

  unsigned char status = UCSRA;
  if ( is_empty(uart.txbuf) && (status & _BV(UDRE))){
    // Fifo is empty and UDRE, so send byte directly
    UDR = b;
  }else{
    uart.status &= ~UART_TX_EMPTY;
    ret = fifo_putbyte(uart.txbuf, b);
  }

  exit_critical();

  return ret;
}

/**
 * Get a char from UART Rx queue
 *
 * @return the char, if equas to -1, there are some errors occur.
 */
int uart_getchar(void){
  into_critical();

  int ret = fifo_getbyte(uart.rxbuf);
  uart.status &= ~(UART_RECVDATA | UART_RX_FULLY);

  exit_critical();

  return ret;
}

/**
 * Rx complete interrupt handler
 */
void NAKED SIG_UART_RECV(void);
void SIG_UART_RECV(void){
  into_critical();

  prologue();
  
  if (!(uart.status & UART_RECVDATA)){
    uart.status |= UART_RECVDATA;
    if (uart.hook != NULL) uart.hook(uart.status);
  }

  if (!(UCSRA & (_BV(FE) | _BV(DOR)))){
    unsigned char b = UDR;
    int err = fifo_putbyte(uart.rxbuf, b);
    if (err == -1){
      uart.status |= UART_RX_FULLY;
      if (uart.hook != NULL) uart.hook(uart.status);
    }
  }
  
  epilogue();
}

/**
 * Tx data register empty interrupt handler
 */
void NAKED SIG_UART_TRANS(void);
void SIG_UART_TRANS(void){
  into_critical();

  prologue();
  
  int b = fifo_getbyte(uart.txbuf);
  if (b > 0){
    UDR = b;
  }else{
    uart.status |= UART_TX_EMPTY;
    if (uart.hook != NULL) uart.hook(uart.status);
  }

  epilogue();
}

#endif