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ardupilot/libraries/FastSerial/FastSerial.h

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// -*- Mode: C++; c-basic-offset: 8; indent-tabs-mode: nil -*-
//
// Interrupt-driven serial transmit/receive library.
//
// Copyright (c) 2010 Michael Smith. All rights reserved.
//
// Receive and baudrate calculations derived from the Arduino
// HardwareSerial driver:
//
// Copyright (c) 2006 Nicholas Zambetti. All right reserved.
//
// Transmit algorithm inspired by work:
//
// Code Jose Julio and Jordi Munoz. DIYDrones.com
//
// 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
//
//
// Note that this library does not pre-declare drivers for serial
// ports; the user must explicitly create drivers for the ports they
// wish to use. This is less friendly than the stock Arduino driver,
// but it saves 24 bytes of RAM for every unused port and frees up
// the vector for another driver (e.g. MSPIM on USARTs).
//
#ifndef FastSerial_h
#define FastSerial_h
// disable the stock Arduino serial driver
#ifdef HardwareSerial_h
# error Must include FastSerial.h before the Arduino serial driver is defined.
#endif
#define HardwareSerial_h
#include <inttypes.h>
#include <stdlib.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include "BetterStream.h"
//
// Because Arduino libraries aren't really libraries, but we want to
// only define interrupt handlers for serial ports that are actually
// used, we have to force our users to define them using a macro.
//
// FastSerialPort(<port name>, <port number>)
//
// <port name> is the name of the object that will be created by the
// macro. <port number> is the 0-based number of the port that will
// be managed by the object.
//
// Previously ports were defined with a different macro for each port,
// and these macros are retained for compatibility:
//
// FastSerialPort0(<port name>) creates <port name> referencing serial port 0
// FastSerialPort1(<port name>) creates <port name> referencing serial port 1
// FastSerialPort2(<port name>) creates <port name> referencing serial port 2
// FastSerialPort3(<port name>) creates <port name> referencing serial port 3
//
// Note that compatibility macros are only defined for ports that
// exist on the target device.
//
//
// Forward declarations for clients that want to assume that the
// default Serial* objects exist.
//
// Note that the application is responsible for ensuring that these
// actually get defined, otherwise Arduino will suck in the
// HardwareSerial library and linking will fail.
//
extern class FastSerial Serial;
extern class FastSerial Serial1;
extern class FastSerial Serial2;
extern class FastSerial Serial3;
class FastSerial : public BetterStream {
public:
FastSerial(const uint8_t portNumber,
volatile uint8_t *ubrrh,
volatile uint8_t *ubrrl,
volatile uint8_t *ucsra,
volatile uint8_t *ucsrb,
const uint8_t u2x,
const uint8_t portEnableBits,
const uint8_t portTxBits);
// Serial API
virtual void begin(long baud);
virtual void begin(long baud, unsigned int rxSpace, unsigned int txSpace);
virtual void end(void);
virtual int available(void);
virtual int read(void);
virtual int peek(void);
virtual void flush(void);
virtual void write(uint8_t c);
using BetterStream::write;
// public so the interrupt handlers can see it
struct Buffer {
volatile uint16_t head, tail;
uint16_t mask;
uint8_t *bytes;
};
private:
// register accessors
volatile uint8_t *_ubrrh;
volatile uint8_t *_ubrrl;
volatile uint8_t *_ucsra;
volatile uint8_t *_ucsrb;
// register magic numbers
uint8_t _portEnableBits; // rx, tx and rx interrupt enables
uint8_t _portTxBits; // tx data and completion interrupt enables
uint8_t _u2x;
// ring buffers
Buffer *_rxBuffer;
Buffer *_txBuffer;
bool _open;
static bool _allocBuffer(Buffer *buffer, unsigned int size);
static void _freeBuffer(Buffer *buffer);
};
// Used by the per-port interrupt vectors
extern FastSerial::Buffer __FastSerial__rxBuffer[];
extern FastSerial::Buffer __FastSerial__txBuffer[];
// Generic Rx/Tx vectors for a serial port - needs to know magic numbers
#define FastSerialHandler(_PORT, _RXVECTOR, _TXVECTOR, _UDR, _UCSRB, _TXBITS) \
ISR(_RXVECTOR, ISR_BLOCK) \
{ \
uint8_t c; \
int16_t i; \
\
/* read the byte as quickly as possible */ \
c = _UDR; \
/* work out where the head will go next */ \
i = (__FastSerial__rxBuffer[_PORT].head + 1) & __FastSerial__rxBuffer[_PORT].mask; \
/* decide whether we have space for another byte */ \
if (i != __FastSerial__rxBuffer[_PORT].tail) { \
/* we do, move the head */ \
__FastSerial__rxBuffer[_PORT].bytes[__FastSerial__rxBuffer[_PORT].head] = c; \
__FastSerial__rxBuffer[_PORT].head = i; \
} \
} \
ISR(_TXVECTOR, ISR_BLOCK) \
{ \
/* if there is another character to send */ \
if (__FastSerial__txBuffer[_PORT].tail != __FastSerial__txBuffer[_PORT].head) { \
_UDR = __FastSerial__txBuffer[_PORT].bytes[__FastSerial__txBuffer[_PORT].tail]; \
/* increment the tail */ \
__FastSerial__txBuffer[_PORT].tail = \
(__FastSerial__txBuffer[_PORT].tail + 1) & __FastSerial__txBuffer[_PORT].mask; \
} else { \
/* there are no more bytes to send, disable the interrupt */ \
if (__FastSerial__txBuffer[_PORT].head == __FastSerial__txBuffer[_PORT].tail) \
_UCSRB &= ~_TXBITS; \
} \
} \
struct hack
//
// Portability; convert various older sets of defines for U(S)ART0 up
// to match the definitions for the 1280 and later devices.
//
#if !defined(USART0_RX_vect)
# if defined(USART_RX_vect)
# define USART0_RX_vect USART_RX_vect
# define USART0_UDRE_vect USART_UDRE_vect
# elif defined(UART0_RX_vect)
# define USART0_RX_vect UART0_RX_vect
# define USART0_UDRE_vect UART0_UDRE_vect
# endif
#endif
#if !defined(USART1_RX_vect)
# if defined(UART1_RX_vect)
# define USART1_RX_vect UART1_RX_vect
# define USART1_UDRE_vect UART1_UDRE_vect
# endif
#endif
#if !defined(UDR0)
# if defined(UDR)
# define UDR0 UDR
# define UBRR0H UBRRH
# define UBRR0L UBRRL
# define UCSR0A UCSRA
# define UCSR0B UCSRB
# define U2X0 U2X
# define RXEN0 RXEN
# define TXEN0 TXEN
# define RXCIE0 RXCIE
# define UDRIE0 UDRIE
# endif
#endif
//
// Macro defining a FastSerial port instance.
//
#define FastSerialPort(_name, _num) \
FastSerial _name(_num, \
&UBRR##_num##H, \
&UBRR##_num##L, \
&UCSR##_num##A, \
&UCSR##_num##B, \
U2X##_num, \
(_BV(RXEN##_num) | _BV(TXEN##_num) | _BV(RXCIE##_num)), \
(_BV(UDRIE##_num))); \
FastSerialHandler(_num, \
USART##_num##_RX_vect, \
USART##_num##_UDRE_vect, \
UDR##_num, \
UCSR##_num##B, \
_BV(UDRIE##_num))
//
// Compatibility macros for previous FastSerial versions.
//
// Note that these are not conditionally defined, as the errors
// generated when using these macros for a board that does not support
// the port are better than the errors generated for a macro that's not
// defined at all.
//
#define FastSerialPort0(_portName) FastSerialPort(_portName, 0)
#define FastSerialPort1(_portName) FastSerialPort(_portName, 1)
#define FastSerialPort2(_portName) FastSerialPort(_portName, 2)
#define FastSerialPort3(_portName) FastSerialPort(_portName, 3)
#endif // FastSerial_h
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