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Arduino/hardware/arduino/sam/cores/arduino/USARTClass.cpp
2012-05-20 23:45:56 +02:00

139 lines
3.7 KiB
C++

/*
Copyright (c) 2011 Arduino. All right reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "USARTClass.h"
// Constructors ////////////////////////////////////////////////////////////////
USARTClass::USARTClass( Usart* pUsart, IRQn_Type dwIrq, uint32_t dwId, RingBuffer* pRx_buffer )
{
_rx_buffer = pRx_buffer ;
_pUsart=pUsart ;
_dwIrq=dwIrq ;
_dwId=dwId ;
}
// Public Methods //////////////////////////////////////////////////////////////
void USARTClass::begin( const uint32_t dwBaudRate )
{
// Configure PMC
pmc_enable_periph_clk( _dwId ) ;
// Disable PDC channel
_pUsart->US_PTCR = US_PTCR_RXTDIS | US_PTCR_TXTDIS ;
// Reset and disable receiver and transmitter
_pUsart->US_CR = US_CR_RSTRX | US_CR_RSTTX | US_CR_RXDIS | US_CR_TXDIS ;
// Configure mode
_pUsart->US_MR = US_MR_USART_MODE_NORMAL | US_MR_USCLKS_MCK | US_MR_CHRL_8_BIT | US_MR_PAR_NO |
US_MR_NBSTOP_1_BIT | US_MR_CHMODE_NORMAL;
// Configure baudrate, asynchronous no oversampling
_pUsart->US_BRGR = (SystemCoreClock / dwBaudRate) / 16 ;
// Configure interrupts
_pUsart->US_IDR = 0xFFFFFFFF;
_pUsart->US_IER = US_IER_RXRDY | US_IER_OVRE | US_IER_FRAME;
// Enable UART interrupt in NVIC
NVIC_EnableIRQ( _dwIrq ) ;
// Enable receiver and transmitter
_pUsart->US_CR = US_CR_RXEN | US_CR_TXEN ;
}
void USARTClass::end( void )
{
// clear any received data
_rx_buffer->_iHead = _rx_buffer->_iTail ;
// Disable UART interrupt in NVIC
NVIC_DisableIRQ( _dwIrq ) ;
// Wait for any outstanding data to be sent
flush();
pmc_disable_periph_clk( _dwId ) ;
}
int USARTClass::available( void )
{
return (uint32_t)(SERIAL_BUFFER_SIZE + _rx_buffer->_iHead - _rx_buffer->_iTail) % SERIAL_BUFFER_SIZE ;
}
int USARTClass::peek( void )
{
if ( _rx_buffer->_iHead == _rx_buffer->_iTail )
return -1 ;
return _rx_buffer->_aucBuffer[_rx_buffer->_iTail] ;
}
int USARTClass::read( void )
{
// if the head isn't ahead of the tail, we don't have any characters
if ( _rx_buffer->_iHead == _rx_buffer->_iTail )
return -1 ;
uint8_t uc = _rx_buffer->_aucBuffer[_rx_buffer->_iTail] ;
_rx_buffer->_iTail = (unsigned int)(_rx_buffer->_iTail + 1) % SERIAL_BUFFER_SIZE ;
return uc ;
}
void USARTClass::flush( void )
{
// Wait for transmission to complete
while ((_pUsart->US_CSR & US_CSR_TXRDY) != US_CSR_TXRDY)
;
}
size_t USARTClass::write( const uint8_t uc_data )
{
// Check if the transmitter is ready
while ((_pUsart->US_CSR & US_CSR_TXRDY) != US_CSR_TXRDY)
;
// Send character
_pUsart->US_THR = uc_data ;
return 1;
}
void USARTClass::IrqHandler( void )
{
uint32_t status = _pUsart->US_CSR;
// Did we receive data ?
if ((status & US_CSR_RXRDY) == US_CSR_RXRDY)
_rx_buffer->store_char( _pUsart->US_RHR ) ;
// Acknowledge errors
if ((status & US_CSR_OVRE) == US_CSR_OVRE ||
(status & US_CSR_FRAME) == US_CSR_FRAME)
{
// TODO: error reporting outside ISR
_pUsart->US_CR |= US_CR_RSTSTA;
}
}