124 lines
4.4 KiB
C
124 lines
4.4 KiB
C
/*
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HardwareSerial_private.h - Hardware serial library for Wiring
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Copyright (c) 2006 Nicholas Zambetti. All right reserved.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Modified 23 November 2006 by David A. Mellis
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Modified 28 September 2010 by Mark Sproul
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Modified 14 August 2012 by Alarus
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*/
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#include "wiring_private.h"
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// this next line disables the entire HardwareSerial.cpp,
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// this is so I can support Attiny series and any other chip without a uart
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#if defined(HAVE_HWSERIAL0) || defined(HAVE_HWSERIAL1) || defined(HAVE_HWSERIAL2) || defined(HAVE_HWSERIAL3)
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// Ensure that the various bit positions we use are available with a 0
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// postfix, so we can always use the values for UART0 for all UARTs. The
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// alternative, passing the various values for each UART to the
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// HardwareSerial constructor also works, but makes the code bigger and
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// slower.
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#if !defined(TXC0)
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#if defined(TXC)
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// Some chips like ATmega8 don't have UPE, only PE. The other bits are
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// named as expected.
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#if !defined(UPE) && defined(PE)
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#define UPE PE
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#endif
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// On ATmega8, the uart and its bits are not numbered, so there is no TXC0 etc.
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#define TXC0 TXC
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#define RXEN0 RXEN
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#define TXEN0 TXEN
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#define RXCIE0 RXCIE
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#define UDRIE0 UDRIE
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#define U2X0 U2X
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#define UPE0 UPE
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#define UDRE0 UDRE
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#elif defined(TXC1)
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// Some devices have uart1 but no uart0
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#define TXC0 TXC1
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#define RXEN0 RXEN1
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#define TXEN0 TXEN1
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#define RXCIE0 RXCIE1
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#define UDRIE0 UDRIE1
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#define U2X0 U2X1
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#define UPE0 UPE1
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#define UDRE0 UDRE1
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#else
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#error No UART found in HardwareSerial.cpp
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#endif
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#endif // !defined TXC0
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// Check at compiletime that it is really ok to use the bit positions of
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// UART0 for the other UARTs as well, in case these values ever get
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// changed for future hardware.
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#if defined(TXC1) && (TXC1 != TXC0 || RXEN1 != RXEN0 || RXCIE1 != RXCIE0 || \
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UDRIE1 != UDRIE0 || U2X1 != U2X0 || UPE1 != UPE0 || \
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UDRE1 != UDRE0)
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#error "Not all bit positions for UART1 are the same as for UART0"
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#endif
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#if defined(TXC2) && (TXC2 != TXC0 || RXEN2 != RXEN0 || RXCIE2 != RXCIE0 || \
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UDRIE2 != UDRIE0 || U2X2 != U2X0 || UPE2 != UPE0 || \
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UDRE2 != UDRE0)
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#error "Not all bit positions for UART2 are the same as for UART0"
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#endif
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#if defined(TXC3) && (TXC3 != TXC0 || RXEN3 != RXEN0 || RXCIE3 != RXCIE0 || \
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UDRIE3 != UDRIE0 || U3X3 != U3X0 || UPE3 != UPE0 || \
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UDRE3 != UDRE0)
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#error "Not all bit positions for UART3 are the same as for UART0"
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#endif
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// Constructors ////////////////////////////////////////////////////////////////
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HardwareSerial::HardwareSerial(
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volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
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volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
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volatile uint8_t *ucsrc, volatile uint8_t *udr) :
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_ubrrh(ubrrh), _ubrrl(ubrrl),
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_ucsra(ucsra), _ucsrb(ucsrb), _ucsrc(ucsrc),
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_udr(udr),
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_rx_buffer_head(0), _rx_buffer_tail(0),
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_tx_buffer_head(0), _tx_buffer_tail(0)
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{
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}
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// Actual interrupt handlers //////////////////////////////////////////////////////////////
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void HardwareSerial::_rx_complete_irq(void)
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{
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if (bit_is_clear(*_ucsra, UPE0)) {
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// No Parity error, read byte and store it in the buffer if there is
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// room
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unsigned char c = *_udr;
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rx_buffer_index_t i = (unsigned int)(_rx_buffer_head + 1) % SERIAL_RX_BUFFER_SIZE;
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// if we should be storing the received character into the location
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// just before the tail (meaning that the head would advance to the
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// current location of the tail), we're about to overflow the buffer
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// and so we don't write the character or advance the head.
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if (i != _rx_buffer_tail) {
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_rx_buffer[_rx_buffer_head] = c;
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_rx_buffer_head = i;
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}
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} else {
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// Parity error, read byte but discard it
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*_udr;
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};
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}
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#endif // whole file
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