mirror of https://github.com/ArduPilot/ardupilot
335 lines
13 KiB
C++
335 lines
13 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
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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 a few bytes of RAM for every unused port and frees up
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// the vector for another driver (e.g. MSPIM on USARTs).
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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 <stdlib.h>
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include "BetterStream.h"
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/// @file FastSerial.h
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/// @brief An enhanced version of the Arduino HardwareSerial class
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/// implementing interrupt-driven transmission and flexible
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/// buffer management.
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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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/// FastSerialPort(<port name>, <port number>)
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///
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/// <port name> is the name of the object that will be created by the
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/// macro. <port number> is the 0-based number of the port that will
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/// be managed by the object.
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///
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/// Previously ports were defined with a different macro for each port,
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/// and these macros are retained for compatibility:
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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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/// Note that compatibility macros are only defined for ports that
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/// exist on the target device.
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///
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/// @name Compatibility
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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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//@}
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/// The FastSerial class definition
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///
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class FastSerial: public BetterStream {
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public:
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/// Constructor
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FastSerial(const uint8_t portNumber, volatile uint8_t *ubrrh, volatile uint8_t *ubrrl, volatile uint8_t *ucsra,
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volatile uint8_t *ucsrb, const uint8_t u2x, const uint8_t portEnableBits, const uint8_t portTxBits);
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/// @name Serial API
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//@{
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virtual void begin(long baud);
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virtual void end(void);
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virtual int available(void);
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virtual int txspace(void);
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virtual int read(void);
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virtual int peek(void);
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virtual void flush(void);
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#if defined(ARDUINO) && ARDUINO >= 100
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virtual size_t write(uint8_t c);
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#else
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virtual void write(uint8_t c);
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#endif
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using BetterStream::write;
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//@}
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/// Extended port open method
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///
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/// Allows for both opening with specified buffer sizes, and re-opening
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/// to adjust a subset of the port's settings.
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///
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/// @note Buffer sizes greater than ::_max_buffer_size will be rounded
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/// down.
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///
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/// @param baud Selects the speed that the port will be
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/// configured to. If zero, the port speed is left
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/// unchanged.
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/// @param rxSpace Sets the receive buffer size for the port. If zero
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/// then the buffer size is left unchanged if the port
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/// is open, or set to ::_default_rx_buffer_size if it is
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/// currently closed.
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/// @param txSpace Sets the transmit buffer size for the port. If zero
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/// then the buffer size is left unchanged if the port
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/// is open, or set to ::_default_tx_buffer_size if it
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/// is currently closed.
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///
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virtual void begin(long baud, unsigned int rxSpace, unsigned int txSpace);
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/// Transmit/receive buffer descriptor.
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///
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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; ///< head and tail pointers
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uint16_t mask; ///< buffer size mask for pointer wrap
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uint8_t *bytes; ///< pointer to allocated buffer
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};
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/// Tell if the serial port has been initialized
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static bool getInitialized(uint8_t port) {
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return (1<<port) & _serialInitialized;
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}
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// ask for writes to be blocking or non-blocking
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void set_blocking_writes(bool blocking) {
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_nonblocking_writes = !blocking;
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}
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private:
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/// Bit mask for initialized ports
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static uint8_t _serialInitialized;
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/// Set if the serial port has been initialized
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static void setInitialized(uint8_t port) {
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_serialInitialized |= (1<<port);
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}
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// register accessors
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volatile uint8_t * const _ubrrh;
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volatile uint8_t * const _ubrrl;
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volatile uint8_t * const _ucsra;
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volatile uint8_t * const _ucsrb;
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// register magic numbers
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const uint8_t _u2x;
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const uint8_t _portEnableBits; ///< rx, tx and rx interrupt enables
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const uint8_t _portTxBits; ///< tx data and completion interrupt enables
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// ring buffers
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Buffer * const _rxBuffer;
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Buffer * const _txBuffer;
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bool _open;
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// whether writes to the port should block waiting
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// for enough space to appear
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bool _nonblocking_writes;
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/// Allocates a buffer of the given size
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///
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/// @param buffer The buffer descriptor for which the buffer will
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/// will be allocated.
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/// @param size The desired buffer size.
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/// @returns True if the buffer was allocated successfully.
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///
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static bool _allocBuffer(Buffer *buffer, unsigned int size);
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/// Frees the allocated buffer in a descriptor
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///
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/// @param buffer The descriptor whose buffer should be freed.
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///
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static void _freeBuffer(Buffer *buffer);
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/// default receive buffer size
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static const unsigned int _default_rx_buffer_size = 128;
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/// default transmit buffer size
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static const unsigned int _default_tx_buffer_size = 16;
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/// maxium tx/rx buffer size
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/// @note if we could bring the max size down to 256, the mask and head/tail
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/// pointers in the buffer could become uint8_t.
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///
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static const unsigned int _max_buffer_size = 512;
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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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///
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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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uint16_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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//
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// Portability; convert various older sets of defines for U(S)ART0 up
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// to match the definitions for the 1280 and later devices.
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//
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#if !defined(USART0_RX_vect)
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# if defined(USART_RX_vect)
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# define USART0_RX_vect USART_RX_vect
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# define USART0_UDRE_vect USART_UDRE_vect
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# elif defined(UART0_RX_vect)
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# define USART0_RX_vect UART0_RX_vect
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# define USART0_UDRE_vect UART0_UDRE_vect
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# endif
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#endif
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#if !defined(USART1_RX_vect)
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# if defined(UART1_RX_vect)
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# define USART1_RX_vect UART1_RX_vect
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# define USART1_UDRE_vect UART1_UDRE_vect
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# endif
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#endif
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#if !defined(UDR0)
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# if defined(UDR)
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# define UDR0 UDR
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# define UBRR0H UBRRH
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# define UBRR0L UBRRL
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# define UCSR0A UCSRA
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# define UCSR0B UCSRB
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# define U2X0 U2X
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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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# endif
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#endif
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///
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/// Macro defining a FastSerial port instance.
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///
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#define FastSerialPort(_name, _num) \
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FastSerial _name(_num, \
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&UBRR##_num##H, \
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&UBRR##_num##L, \
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&UCSR##_num##A, \
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&UCSR##_num##B, \
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U2X##_num, \
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(_BV(RXEN##_num) | _BV(TXEN##_num) | _BV(RXCIE##_num)), \
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(_BV(UDRIE##_num))); \
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FastSerialHandler(_num, \
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USART##_num##_RX_vect, \
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USART##_num##_UDRE_vect, \
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UDR##_num, \
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UCSR##_num##B, \
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_BV(UDRIE##_num))
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///
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/// Compatibility macros for previous FastSerial versions.
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///
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/// Note that these are not conditionally defined, as the errors
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/// generated when using these macros for a board that does not support
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/// the port are better than the errors generated for a macro that's not
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/// defined at all.
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///
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#define FastSerialPort0(_portName) FastSerialPort(_portName, 0)
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#define FastSerialPort1(_portName) FastSerialPort(_portName, 1)
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#define FastSerialPort2(_portName) FastSerialPort(_portName, 2)
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#define FastSerialPort3(_portName) FastSerialPort(_portName, 3)
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#endif // FastSerial_h
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