mirror of
https://github.com/arduino/Arduino.git
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a6a59f1783
This reverts commitdf9835efaf
, reversing changes made toec45af8bfa
. Conflicts: hardware/arduino/variants/mega/pins_arduino.h libraries/Ethernet/examples/PachubeClientString/PachubeClientString.ino
516 lines
13 KiB
C++
Executable File
516 lines
13 KiB
C++
Executable File
/*
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SoftwareSerial.cpp (formerly NewSoftSerial.cpp) -
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Multi-instance software serial library for Arduino/Wiring
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-- Interrupt-driven receive and other improvements by ladyada
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(http://ladyada.net)
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-- Tuning, circular buffer, derivation from class Print/Stream,
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multi-instance support, porting to 8MHz processors,
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various optimizations, PROGMEM delay tables, inverse logic and
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direct port writing by Mikal Hart (http://www.arduiniana.org)
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-- Pin change interrupt macros by Paul Stoffregen (http://www.pjrc.com)
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-- 20MHz processor support by Garrett Mace (http://www.macetech.com)
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-- ATmega1280/2560 support by Brett Hagman (http://www.roguerobotics.com/)
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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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The latest version of this library can always be found at
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http://arduiniana.org.
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*/
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// When set, _DEBUG co-opts pins 11 and 13 for debugging with an
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// oscilloscope or logic analyzer. Beware: it also slightly modifies
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// the bit times, so don't rely on it too much at high baud rates
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#define _DEBUG 0
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#define _DEBUG_PIN1 11
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#define _DEBUG_PIN2 13
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//
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// Includes
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//
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#include <avr/interrupt.h>
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#include <avr/pgmspace.h>
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#include "Arduino.h"
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#include "SoftwareSerial.h"
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//
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// Lookup table
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//
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typedef struct _DELAY_TABLE
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{
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long baud;
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unsigned short rx_delay_centering;
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unsigned short rx_delay_intrabit;
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unsigned short rx_delay_stopbit;
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unsigned short tx_delay;
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} DELAY_TABLE;
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#if F_CPU == 16000000
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static const DELAY_TABLE PROGMEM table[] =
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{
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// baud rxcenter rxintra rxstop tx
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{ 115200, 1, 17, 17, 12, },
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{ 57600, 10, 37, 37, 33, },
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{ 38400, 25, 57, 57, 54, },
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{ 31250, 31, 70, 70, 68, },
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{ 28800, 34, 77, 77, 74, },
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{ 19200, 54, 117, 117, 114, },
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{ 14400, 74, 156, 156, 153, },
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{ 9600, 114, 236, 236, 233, },
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{ 4800, 233, 474, 474, 471, },
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{ 2400, 471, 950, 950, 947, },
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{ 1200, 947, 1902, 1902, 1899, },
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{ 300, 3804, 7617, 7617, 7614, },
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};
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const int XMIT_START_ADJUSTMENT = 5;
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#elif F_CPU == 8000000
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static const DELAY_TABLE table[] PROGMEM =
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{
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// baud rxcenter rxintra rxstop tx
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{ 115200, 1, 5, 5, 3, },
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{ 57600, 1, 15, 15, 13, },
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{ 38400, 2, 25, 26, 23, },
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{ 31250, 7, 32, 33, 29, },
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{ 28800, 11, 35, 35, 32, },
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{ 19200, 20, 55, 55, 52, },
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{ 14400, 30, 75, 75, 72, },
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{ 9600, 50, 114, 114, 112, },
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{ 4800, 110, 233, 233, 230, },
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{ 2400, 229, 472, 472, 469, },
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{ 1200, 467, 948, 948, 945, },
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{ 300, 1895, 3805, 3805, 3802, },
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};
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const int XMIT_START_ADJUSTMENT = 4;
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#elif F_CPU == 20000000
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// 20MHz support courtesy of the good people at macegr.com.
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// Thanks, Garrett!
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static const DELAY_TABLE PROGMEM table[] =
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{
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// baud rxcenter rxintra rxstop tx
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{ 115200, 3, 21, 21, 18, },
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{ 57600, 20, 43, 43, 41, },
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{ 38400, 37, 73, 73, 70, },
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{ 31250, 45, 89, 89, 88, },
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{ 28800, 46, 98, 98, 95, },
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{ 19200, 71, 148, 148, 145, },
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{ 14400, 96, 197, 197, 194, },
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{ 9600, 146, 297, 297, 294, },
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{ 4800, 296, 595, 595, 592, },
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{ 2400, 592, 1189, 1189, 1186, },
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{ 1200, 1187, 2379, 2379, 2376, },
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{ 300, 4759, 9523, 9523, 9520, },
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};
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const int XMIT_START_ADJUSTMENT = 6;
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#else
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#error This version of SoftwareSerial supports only 20, 16 and 8MHz processors
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#endif
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//
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// Statics
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//
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SoftwareSerial *SoftwareSerial::active_object = 0;
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char SoftwareSerial::_receive_buffer[_SS_MAX_RX_BUFF];
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volatile uint8_t SoftwareSerial::_receive_buffer_tail = 0;
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volatile uint8_t SoftwareSerial::_receive_buffer_head = 0;
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//
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// Debugging
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//
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// This function generates a brief pulse
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// for debugging or measuring on an oscilloscope.
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inline void DebugPulse(uint8_t pin, uint8_t count)
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{
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#if _DEBUG
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volatile uint8_t *pport = portOutputRegister(digitalPinToPort(pin));
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uint8_t val = *pport;
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while (count--)
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{
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*pport = val | digitalPinToBitMask(pin);
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*pport = val;
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}
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#endif
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}
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//
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// Private methods
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//
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/* static */
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inline void SoftwareSerial::tunedDelay(uint16_t delay) {
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uint8_t tmp=0;
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asm volatile("sbiw %0, 0x01 \n\t"
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"ldi %1, 0xFF \n\t"
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"cpi %A0, 0xFF \n\t"
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"cpc %B0, %1 \n\t"
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"brne .-10 \n\t"
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: "+r" (delay), "+a" (tmp)
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: "0" (delay)
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);
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}
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// This function sets the current object as the "listening"
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// one and returns true if it replaces another
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bool SoftwareSerial::listen()
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{
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if (active_object != this)
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{
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_buffer_overflow = false;
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uint8_t oldSREG = SREG;
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cli();
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_receive_buffer_head = _receive_buffer_tail = 0;
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active_object = this;
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SREG = oldSREG;
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return true;
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}
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return false;
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}
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//
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// The receive routine called by the interrupt handler
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//
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void SoftwareSerial::recv()
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{
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#if GCC_VERSION < 40302
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// Work-around for avr-gcc 4.3.0 OSX version bug
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// Preserve the registers that the compiler misses
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// (courtesy of Arduino forum user *etracer*)
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asm volatile(
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"push r18 \n\t"
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"push r19 \n\t"
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"push r20 \n\t"
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"push r21 \n\t"
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"push r22 \n\t"
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"push r23 \n\t"
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"push r26 \n\t"
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"push r27 \n\t"
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::);
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#endif
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uint8_t d = 0;
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// If RX line is high, then we don't see any start bit
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// so interrupt is probably not for us
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if (_inverse_logic ? rx_pin_read() : !rx_pin_read())
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{
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// Wait approximately 1/2 of a bit width to "center" the sample
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tunedDelay(_rx_delay_centering);
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DebugPulse(_DEBUG_PIN2, 1);
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// Read each of the 8 bits
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for (uint8_t i=0x1; i; i <<= 1)
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{
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tunedDelay(_rx_delay_intrabit);
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DebugPulse(_DEBUG_PIN2, 1);
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uint8_t noti = ~i;
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if (rx_pin_read())
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d |= i;
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else // else clause added to ensure function timing is ~balanced
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d &= noti;
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}
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// skip the stop bit
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tunedDelay(_rx_delay_stopbit);
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DebugPulse(_DEBUG_PIN2, 1);
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if (_inverse_logic)
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d = ~d;
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// if buffer full, set the overflow flag and return
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if ((_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF != _receive_buffer_head)
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{
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// save new data in buffer: tail points to where byte goes
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_receive_buffer[_receive_buffer_tail] = d; // save new byte
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_receive_buffer_tail = (_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF;
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}
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else
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{
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#if _DEBUG // for scope: pulse pin as overflow indictator
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DebugPulse(_DEBUG_PIN1, 1);
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#endif
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_buffer_overflow = true;
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}
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}
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#if GCC_VERSION < 40302
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// Work-around for avr-gcc 4.3.0 OSX version bug
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// Restore the registers that the compiler misses
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asm volatile(
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"pop r27 \n\t"
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"pop r26 \n\t"
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"pop r23 \n\t"
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"pop r22 \n\t"
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"pop r21 \n\t"
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"pop r20 \n\t"
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"pop r19 \n\t"
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"pop r18 \n\t"
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::);
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#endif
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}
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void SoftwareSerial::tx_pin_write(uint8_t pin_state)
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{
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if (pin_state == LOW)
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*_transmitPortRegister &= ~_transmitBitMask;
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else
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*_transmitPortRegister |= _transmitBitMask;
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}
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uint8_t SoftwareSerial::rx_pin_read()
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{
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return *_receivePortRegister & _receiveBitMask;
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}
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//
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// Interrupt handling
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//
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/* static */
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inline void SoftwareSerial::handle_interrupt()
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{
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if (active_object)
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{
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active_object->recv();
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}
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}
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#if defined(PCINT0_vect)
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ISR(PCINT0_vect)
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{
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SoftwareSerial::handle_interrupt();
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}
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#endif
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#if defined(PCINT1_vect)
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ISR(PCINT1_vect)
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{
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SoftwareSerial::handle_interrupt();
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}
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#endif
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#if defined(PCINT2_vect)
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ISR(PCINT2_vect)
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{
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SoftwareSerial::handle_interrupt();
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}
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#endif
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#if defined(PCINT3_vect)
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ISR(PCINT3_vect)
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{
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SoftwareSerial::handle_interrupt();
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}
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#endif
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//
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// Constructor
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//
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SoftwareSerial::SoftwareSerial(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic /* = false */) :
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_rx_delay_centering(0),
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_rx_delay_intrabit(0),
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_rx_delay_stopbit(0),
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_tx_delay(0),
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_buffer_overflow(false),
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_inverse_logic(inverse_logic)
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{
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setTX(transmitPin);
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setRX(receivePin);
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}
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//
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// Destructor
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//
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SoftwareSerial::~SoftwareSerial()
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{
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end();
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}
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void SoftwareSerial::setTX(uint8_t tx)
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{
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pinMode(tx, OUTPUT);
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digitalWrite(tx, HIGH);
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_transmitBitMask = digitalPinToBitMask(tx);
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uint8_t port = digitalPinToPort(tx);
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_transmitPortRegister = portOutputRegister(port);
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}
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void SoftwareSerial::setRX(uint8_t rx)
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{
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pinMode(rx, INPUT);
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if (!_inverse_logic)
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digitalWrite(rx, HIGH); // pullup for normal logic!
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_receivePin = rx;
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_receiveBitMask = digitalPinToBitMask(rx);
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uint8_t port = digitalPinToPort(rx);
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_receivePortRegister = portInputRegister(port);
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}
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//
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// Public methods
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//
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void SoftwareSerial::begin(long speed)
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{
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_rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay = 0;
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for (unsigned i=0; i<sizeof(table)/sizeof(table[0]); ++i)
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{
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long baud = pgm_read_dword(&table[i].baud);
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if (baud == speed)
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{
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_rx_delay_centering = pgm_read_word(&table[i].rx_delay_centering);
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_rx_delay_intrabit = pgm_read_word(&table[i].rx_delay_intrabit);
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_rx_delay_stopbit = pgm_read_word(&table[i].rx_delay_stopbit);
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_tx_delay = pgm_read_word(&table[i].tx_delay);
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break;
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}
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}
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// Set up RX interrupts, but only if we have a valid RX baud rate
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if (_rx_delay_stopbit)
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{
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if (digitalPinToPCICR(_receivePin))
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{
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*digitalPinToPCICR(_receivePin) |= _BV(digitalPinToPCICRbit(_receivePin));
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*digitalPinToPCMSK(_receivePin) |= _BV(digitalPinToPCMSKbit(_receivePin));
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}
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tunedDelay(_tx_delay); // if we were low this establishes the end
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}
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#if _DEBUG
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pinMode(_DEBUG_PIN1, OUTPUT);
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pinMode(_DEBUG_PIN2, OUTPUT);
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#endif
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listen();
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}
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void SoftwareSerial::end()
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{
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if (digitalPinToPCMSK(_receivePin))
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*digitalPinToPCMSK(_receivePin) &= ~_BV(digitalPinToPCMSKbit(_receivePin));
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}
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// Read data from buffer
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int SoftwareSerial::read()
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{
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if (!isListening())
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return -1;
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// Empty buffer?
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if (_receive_buffer_head == _receive_buffer_tail)
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return -1;
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// Read from "head"
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uint8_t d = _receive_buffer[_receive_buffer_head]; // grab next byte
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_receive_buffer_head = (_receive_buffer_head + 1) % _SS_MAX_RX_BUFF;
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return d;
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}
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int SoftwareSerial::available()
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{
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if (!isListening())
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return 0;
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return (_receive_buffer_tail + _SS_MAX_RX_BUFF - _receive_buffer_head) % _SS_MAX_RX_BUFF;
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}
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size_t SoftwareSerial::write(uint8_t b)
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{
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if (_tx_delay == 0) {
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setWriteError();
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return 0;
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}
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uint8_t oldSREG = SREG;
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cli(); // turn off interrupts for a clean txmit
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// Write the start bit
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tx_pin_write(_inverse_logic ? HIGH : LOW);
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tunedDelay(_tx_delay + XMIT_START_ADJUSTMENT);
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// Write each of the 8 bits
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if (_inverse_logic)
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{
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for (byte mask = 0x01; mask; mask <<= 1)
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{
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if (b & mask) // choose bit
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tx_pin_write(LOW); // send 1
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else
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tx_pin_write(HIGH); // send 0
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tunedDelay(_tx_delay);
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}
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tx_pin_write(LOW); // restore pin to natural state
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}
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else
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{
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for (byte mask = 0x01; mask; mask <<= 1)
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{
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if (b & mask) // choose bit
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tx_pin_write(HIGH); // send 1
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else
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tx_pin_write(LOW); // send 0
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tunedDelay(_tx_delay);
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}
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tx_pin_write(HIGH); // restore pin to natural state
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}
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SREG = oldSREG; // turn interrupts back on
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tunedDelay(_tx_delay);
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return 1;
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}
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void SoftwareSerial::flush()
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{
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if (!isListening())
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return;
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uint8_t oldSREG = SREG;
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cli();
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_receive_buffer_head = _receive_buffer_tail = 0;
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SREG = oldSREG;
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}
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int SoftwareSerial::peek()
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{
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if (!isListening())
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return -1;
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// Empty buffer?
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if (_receive_buffer_head == _receive_buffer_tail)
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return -1;
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// Read from "head"
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return _receive_buffer[_receive_buffer_head];
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}
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