// -*- 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 #include #include #include #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. // // Due to the way interrupt vectors are specified, we have to have // a separate macro for every port. Ugh. // // The macros are: // // FastSerialPort0() creates referencing serial port 0 // FastSerialPort1() creates referencing serial port 1 // FastSerialPort2() creates referencing serial port 2 // FastSerialPort3() creates referencing serial port 3 // // Note that 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