mirror of https://github.com/ArduPilot/ardupilot
251 lines
12 KiB
C++
251 lines
12 KiB
C++
// -*- Mode: C++; c-basic-offset: 8; indent-tabs-mode: nil -*-
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//
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// Interrupt-driven serial transmit/receive library.
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//
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// Copyright (c) 2010 Michael Smith. All rights reserved.
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//
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// Receive and baudrate calculations derived from the Arduino
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// HardwareSerial driver:
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//
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// Copyright (c) 2006 Nicholas Zambetti. All right reserved.
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//
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// Transmit algorithm inspired by work:
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//
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// Code Jose Julio and Jordi Munoz. DIYDrones.com
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//
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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
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// version.
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//
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// This library is distributed in the hope that it will be
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// useful, but WITHOUT ANY WARRANTY; without even the implied
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// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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// PURPOSE. See the GNU Lesser General Public License for more
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// details.
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//
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// You should have received a copy of the GNU Lesser General
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// Public License along with this library; if not, write to the
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// Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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// Boston, MA 02110-1301 USA
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//
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//
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// Note that this library does not pre-declare drivers for serial
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// ports; the user must explicitly create drivers for the ports they
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// wish to use. This is less friendly than the stock Arduino driver,
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// but it saves ~200 bytes for every unused port.
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//
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#ifndef FastSerial_h
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#define FastSerial_h
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// disable the stock Arduino serial driver
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#ifdef HardwareSerial_h
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# error Must include FastSerial.h before the Arduino serial driver is defined.
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#endif
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#define HardwareSerial_h
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#include <inttypes.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <avr/interrupt.h>
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#include "BetterStream.h"
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//
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// Because Arduino libraries aren't really libraries, but we want to
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// only define interrupt handlers for serial ports that are actually
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// used, we have to force our users to define them using a macro.
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//
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// Due to the way interrupt vectors are specified, we have to have
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// a separate macro for every port. Ugh.
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//
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// The macros are:
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//
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// FastSerialPort0(<port name>) creates <port name> referencing serial port 0
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// FastSerialPort1(<port name>) creates <port name> referencing serial port 1
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// FastSerialPort2(<port name>) creates <port name> referencing serial port 2
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// FastSerialPort3(<port name>) creates <port name> referencing serial port 3
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//
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//
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// Forward declarations for clients that want to assume that the
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// default Serial* objects exist.
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//
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// Note that the application is responsible for ensuring that these
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// actually get defined, otherwise Arduino will suck in the
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// HardwareSerial library and linking will fail.
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//
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extern class FastSerial Serial;
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extern class FastSerial Serial1;
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extern class FastSerial Serial2;
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extern class FastSerial Serial3;
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class FastSerial : public BetterStream {
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public:
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FastSerial(const uint8_t portNumber,
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volatile uint8_t *ubrrh,
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volatile uint8_t *ubrrl,
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volatile uint8_t *ucsra,
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volatile uint8_t *ucsrb,
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volatile uint8_t *udr,
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const uint8_t u2x,
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const uint8_t portEnableBits,
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const uint8_t portTxBits);
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// Serial API
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virtual void begin(long baud);
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virtual void begin(long baud, unsigned int rxSpace, unsigned int txSpace);
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virtual void end(void);
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virtual int available(void);
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virtual int read(void);
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virtual void flush(void);
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virtual void write(uint8_t c);
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using BetterStream::write;
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// public so the interrupt handlers can see it
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struct Buffer {
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volatile uint16_t head, tail;
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uint16_t mask;
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uint8_t *bytes;
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};
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private:
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// register accessors
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volatile uint8_t *_ubrrh;
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volatile uint8_t *_ubrrl;
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volatile uint8_t *_ucsra;
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volatile uint8_t *_ucsrb;
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volatile uint8_t *_udr;
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// register magic numbers
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uint8_t _portEnableBits; // rx, tx and rx interrupt enables
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uint8_t _portTxBits; // tx data and completion interrupt enables
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uint8_t _u2x;
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// ring buffers
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Buffer *_rxBuffer;
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Buffer *_txBuffer;
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bool _open;
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bool _allocBuffer(Buffer *buffer, unsigned int size);
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void _freeBuffer(Buffer *buffer);
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};
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// Used by the per-port interrupt vectors
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extern FastSerial::Buffer __FastSerial__rxBuffer[];
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extern FastSerial::Buffer __FastSerial__txBuffer[];
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// Generic Rx/Tx vectors for a serial port - needs to know magic numbers
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#define FastSerialHandler(_PORT, _RXVECTOR, _TXVECTOR, _UDR, _UCSRB, _TXBITS) \
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ISR(_RXVECTOR, ISR_BLOCK) \
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{ \
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uint8_t c; \
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int16_t i; \
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\
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/* read the byte as quickly as possible */ \
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c = _UDR; \
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/* work out where the head will go next */ \
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i = (__FastSerial__rxBuffer[_PORT].head + 1) & __FastSerial__rxBuffer[_PORT].mask; \
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/* decide whether we have space for another byte */ \
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if (i != __FastSerial__rxBuffer[_PORT].tail) { \
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/* we do, move the head */ \
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__FastSerial__rxBuffer[_PORT].bytes[__FastSerial__rxBuffer[_PORT].head] = c; \
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__FastSerial__rxBuffer[_PORT].head = i; \
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} \
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} \
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ISR(_TXVECTOR, ISR_BLOCK) \
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{ \
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/* if there is another character to send */ \
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if (__FastSerial__txBuffer[_PORT].tail != __FastSerial__txBuffer[_PORT].head) { \
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_UDR = __FastSerial__txBuffer[_PORT].bytes[__FastSerial__txBuffer[_PORT].tail]; \
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/* increment the tail */ \
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__FastSerial__txBuffer[_PORT].tail = \
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(__FastSerial__txBuffer[_PORT].tail + 1) & __FastSerial__txBuffer[_PORT].mask; \
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} else { \
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/* there are no more bytes to send, disable the interrupt */ \
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if (__FastSerial__txBuffer[_PORT].head == __FastSerial__txBuffer[_PORT].tail) \
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_UCSRB &= ~_TXBITS; \
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} \
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} \
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struct hack
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// Macros defining serial ports
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#if defined(__AVR_ATmega1280__)
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#define FastSerialPort0(_portName) \
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FastSerial _portName(0, \
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&UBRR0H, \
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&UBRR0L, \
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&UCSR0A, \
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&UCSR0B, \
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&UDR0, \
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U2X0, \
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(_BV(RXEN0) | _BV(TXEN0) | _BV(RXCIE0)), \
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(_BV(UDRIE0))); \
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FastSerialHandler(0, SIG_USART0_RECV, SIG_USART0_DATA, UDR0, UCSR0B, _BV(UDRIE0))
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#define FastSerialPort1(_portName) \
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FastSerial _portName(1, \
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&UBRR1H, \
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&UBRR1L, \
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&UCSR1A, \
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&UCSR1B, \
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&UDR1, \
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U2X1, \
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(_BV(RXEN1) | _BV(TXEN1) | _BV(RXCIE1)), \
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(_BV(UDRIE1))); \
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FastSerialHandler(1, SIG_USART1_RECV, SIG_USART1_DATA, UDR1, UCSR1B, _BV(UDRIE1))
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#define FastSerialPort2(_portName) \
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FastSerial _portName(2, \
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&UBRR2H, \
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&UBRR2L, \
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&UCSR2A, \
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&UCSR2B, \
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&UDR2, \
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U2X2, \
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(_BV(RXEN2) | _BV(TXEN2) | _BV(RXCIE2)), \
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(_BV(UDRIE2))); \
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FastSerialHandler(2, SIG_USART2_RECV, SIG_USART2_DATA, UDR2, UCSR2B, _BV(UDRIE2))
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#define FastSerialPort3(_portName) \
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FastSerial _portName(3, \
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&UBRR3H, \
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&UBRR3L, \
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&UCSR3A, \
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&UCSR3B, \
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&UDR3, \
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U2X3, \
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(_BV(RXEN3) | _BV(TXEN3) | _BV(RXCIE3)), \
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(_BV(UDRIE3))); \
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FastSerialHandler(3, SIG_USART3_RECV, SIG_USART3_DATA, UDR3, UCSR3B, _BV(UDRIE3))
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#else
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#if defined(__AVR_ATmega8__)
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#define FastSerialPort0(_portName) \
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FastSerial _portName(0, \
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&UBRR0H, \
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&UBRR0L, \
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&UCSR0A, \
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&UCSR0B, \
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&UDR0, \
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U2X0, \
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(_BV(RXEN0) | _BV(TXEN0) | _BV(RXCIE0)), \
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(_BV(UDRIE0))); \
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FastSerialHandler(0, SIG_UART_RECV, SIG_UART_DATA, UDR0, UCSR0B, _BV(UDRIE0))
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#else
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// note no SIG_USART_* defines for the 168, 328, etc.
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#define FastSerialPort0(_portName) \
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FastSerial _portName(0, \
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&UBRR0H, \
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&UBRR0L, \
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&UCSR0A, \
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&UCSR0B, \
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&UDR0, \
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U2X0, \
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(_BV(RXEN0) | _BV(TXEN0) | _BV(RXCIE0)), \
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(_BV(UDRIE0))); \
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FastSerialHandler(0, USART_RX_vect, USART_UDRE_vect, UDR0, UCSR0B, _BV(UDRIE0))
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#endif
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#endif
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#endif // FastSerial_h
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