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139 lines
3.1 KiB
C++
139 lines
3.1 KiB
C++
#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "USART.h"
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// Constructors ////////////////////////////////////////////////////////////////
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USARTClass::USARTClass( Usart* pUsart, IRQn_Type dwIrq, uint32_t dwId, RingBuffer* pRx_buffer, RingBuffer* pTx_buffer )
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{
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_rx_buffer = pRx_buffer ;
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_tx_buffer = pTx_buffer ;
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_pUsart=pUsart ;
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_dwIrq=dwIrq ;
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_dwId=dwId ;
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}
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// Public Methods //////////////////////////////////////////////////////////////
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void USARTClass::begin( const uint32_t dwBaudRate )
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{
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/* Configure PMC */
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PMC_EnablePeripheral( _dwId ) ;
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/* Reset and disable receiver & transmitter */
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_pUsart->US_CR = US_CR_RSTRX | US_CR_RSTTX | US_CR_RXDIS | US_CR_TXDIS ;
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/* Configure mode */
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_pUsart->US_MR = US_MR_USART_MODE_NORMAL | US_MR_USCLKS_MCK | US_MR_CHRL_8_BIT | US_MR_PAR_NO |
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US_MR_NBSTOP_1_BIT | US_MR_CHMODE_NORMAL;
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/* Configure baudrate */
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/* Asynchronous, no oversampling */
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_pUsart->US_BRGR = (SystemCoreClock / dwBaudRate) / 16 ;
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/* Disable PDC channel */
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_pUsart->US_PTCR = US_PTCR_RXTDIS | US_PTCR_TXTDIS ;
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/* Enable receiver and transmitter */
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_pUsart->US_CR = US_CR_RXEN | US_CR_TXEN ;
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}
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void USARTClass::end()
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{
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// wait for transmission of outgoing data
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while ( _tx_buffer->_iHead != _tx_buffer->_iTail )
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{
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}
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// clear any received data
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_rx_buffer->_iHead = _rx_buffer->_iTail ;
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PMC_DisablePeripheral( _dwId ) ;
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}
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int USARTClass::available( void )
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{
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return (unsigned int)(SERIAL_BUFFER_SIZE + _rx_buffer->_iHead - _rx_buffer->_iTail) % SERIAL_BUFFER_SIZE ;
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}
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int USARTClass::peek( void )
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{
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if ( _rx_buffer->_iHead == _rx_buffer->_iTail )
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{
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return -1 ;
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}
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else
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{
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return _rx_buffer->_aucBuffer[_rx_buffer->_iTail] ;
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}
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}
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int USARTClass::read( void )
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{
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// if the _iHead isn't ahead of the _iTail, we don't have any characters
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if ( _rx_buffer->_iHead == _rx_buffer->_iTail )
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{
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return -1 ;
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}
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else
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{
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unsigned char c = _rx_buffer->_aucBuffer[_rx_buffer->_iTail] ;
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_rx_buffer->_iTail = (unsigned int)(_rx_buffer->_iTail + 1) % SERIAL_BUFFER_SIZE ;
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return c ;
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}
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}
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void USARTClass::flush( void )
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{
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while ( _tx_buffer->_iHead != _tx_buffer->_iTail )
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{
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}
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}
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void USARTClass::write( uint8_t uc )
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{
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int i = (_tx_buffer->_iHead + 1) % SERIAL_BUFFER_SIZE ;
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// If the output buffer is full, there's nothing for it other than to
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// wait for the interrupt handler to empty it a bit
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while ( i == _tx_buffer->_iTail )
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{
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}
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_tx_buffer->_aucBuffer[_tx_buffer->_iHead] = uc ;
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_tx_buffer->_iHead = i ;
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/* Wait for the transmitter to be ready */
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while ( (_pUsart->US_CSR & US_CSR_TXEMPTY) == 0 ) ;
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/* Send character */
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_pUsart->US_THR=uc ;
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}
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void USARTClass::IrqHandler( void )
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{
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// RX char IT
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uint8_t uc = _pUsart->US_RHR ;
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_rx_buffer->store_char( uc ) ;
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// TX FIFO empty IT
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if ( _tx_buffer->_iHead == _tx_buffer->_iTail )
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{
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// Buffer empty, so disable interrupts
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}
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else
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{
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// There is more data in the output buffer. Send the next byte
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uc = _tx_buffer->_aucBuffer[_tx_buffer->_iTail] ;
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_tx_buffer->_iTail = (_tx_buffer->_iTail + 1) % SERIAL_BUFFER_SIZE ;
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_pUsart->US_THR = uc ;
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}
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}
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