URM37.rar_URM37_超声波

/* NewSoftSerial.cpp - Multi-instance software serial library Copyright (c) 2006 David A. Mellis. All rights reserved. Interrupt-driven receive and other improvements by ladyada Tuning, circular buffer, derivation from class Print, multi-instance support, porting to 8MHz processors by Mikal Hart 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 The latest version of this library can always be found at http://arduiniana.org. */ // When set, _DEBUG co-opts pins 11 and 13 for debugging with an // oscilloscope or logic analyzer. Beware: it also slightly modifies // the bit times, so don't rely on it too much at high baud rates #define _DEBUG 0 // // Includes // #include <stdlib.h> #include <avr/interrupt.h> #include <avr/pgmspace.h> #include "WConstants.h" #include "NewSoftSerial.h" // // Lookup table // typedef struct _DELAY_TABLE { long baud; unsigned short rx_delay_centering; unsigned short rx_delay_intrabit; unsigned short rx_delay_stopbit; unsigned short tx_delay; } DELAY_TABLE; #if F_CPU == 16000000 static const DELAY_TABLE PROGMEM table[] = { // baud rxcntr rxintra rxstop tx { 115200, 0, 0, 0, 8, }, { 57600, /*7*/2, /*25,*/24, /*31,28*/25, 28, }, { 38400, /*17*/8, 45, /*51*/38, 48, }, { 31250, 23, 56, 62, 62, }, { 28800, 27, 64, /*70*/66, 66, }, { 19200, 46, 102, 108, 108, }, { 14400, 68, 146, 152, 152, }, { 9600, 105, 220, 226, 226, }, { 4800, 224, 458, 464, 464, }, { 2400, 462, 934, 940, 940, }, { 1200, 926, 1862, 1868, 1868, }, { 300, 3710, 7430, 7436, 7436, }, }; #elif F_CPU == 8000000 static const DELAY_TABLE table[] PROGMEM = { // baud rxcntr rxintra rxstop tx { 57600, 0, /*5*/5, /*8*/3, /*6*/8, }, { 38400, /*5*/1, /*15*/16, /*18*/16, /*16*/18, }, { 31250, /*8*//*2*/3, /*21*/23, /*24, 23*/23, 24, }, { 28800, /*10*//*3*/4, /*25*/26, /*28*/24, /*26*/28, }, { 19200, /*19*//*3,5*/5, /*44,45*/45, 43, 47, }, { 14400, /*30*/8, 66, /*69*/66, 69, }, { 9600, 49, 103, 106, 106, }, { 4800, 108, 222, 225, 225, }, { 2400, 227, 460, 463, 463, }, { 1200, 459, 924, 927, 927, }, { 300, 1851, 3708, 3711, 3711, }, }; #else #error This version of NewSoftSerial supports only 16 and 8MHz processors #endif // // Statics // NewSoftSerial *NewSoftSerial::active_object = 0; char NewSoftSerial::_receive_buffer[_NewSS_MAX_RX_BUFF]; volatile uint8_t NewSoftSerial::_receive_buffer_tail = 0; volatile uint8_t NewSoftSerial::_receive_buffer_head = 0; // // Private methods // /* static */ void NewSoftSerial::tunedDelay(uint16_t delay) { uint8_t tmp=0; asm volatile("sbiw %0, 0x01 \n\t" "ldi %1, 0xFF \n\t" "cpi %A0, 0xFF \n\t" "cpc %B0, %1 \n\t" "brne .-10 \n\t" : "+r" (delay), "+a" (tmp) : "0" (delay) ); } // This function sets the current object as the "active" // one and returns true if it replaces another bool NewSoftSerial::activate(void) { if (active_object != this) { _buffer_overflow = false; uint8_t oldSREG = SREG; cli(); _receive_buffer_head = _receive_buffer_tail = 0; active_object = this; SREG = oldSREG; return true; } return false; } // // The receive routine called by the interrupt handler // void NewSoftSerial::recv() { #if GCC_VERSION < 40302 // Work-around for avr-gcc 4.3.0 OSX version bug // Preserve the registers that the compiler misses // (courtesy of Arduino forum user *etracer*) asm volatile( "push r18 \n\t" "push r19 \n\t" "push r20 \n\t" "push r21 \n\t" "push r22 \n\t" "push r23 \n\t" "push r26 \n\t" "push r27 \n\t" ::); #endif char i, d = 0; // If RX line is high, then we don't see any start bit // so interrupt is probably not for us if (!digitalRead(_receivePin)) { // Wait approximately 1/2 of a bit width to "center" the sample tunedDelay(_rx_delay_centering); // Read each of the 8 bits for (i=0; i<8; i++) { #if _DEBUG // for scope: bring pin 13 high PORTB |= _BV(5); #endif tunedDelay(_rx_delay_intrabit); // digitalread takes some time #if _DEBUG // for scope: bring pin 13 low PORTB &= ~_BV(5); #endif if (digitalRead(_receivePin)) d |= (1 << i); else // else clause added to ensure function timing is ~balanced d &= ~(1 << i); } // skip the stop bit tunedDelay(_rx_delay_stopbit); // if buffer full, set the overflow flag and return if ((_receive_buffer_tail + 1) % _NewSS_MAX_RX_BUFF != _receive_buffer_head) { // save new data in buffer: tail points to where byte goes _receive_buffer[_receive_buffer_tail] = d; // save new byte _receive_buffer_tail = (_receive_buffer_tail + 1) % _NewSS_MAX_RX_BUFF; } else { #if _DEBUG // for scope: bring pin 11 high: overflow indicator PORTB |= _BV(3); #endif _buffer_overflow = true; } } #if GCC_VERSION < 40302 // Work-around for avr-gcc 4.3.0 OSX version bug // Restore the registers that the compiler misses asm volatile( "pop r27 \n\t" "pop r26 \n\t" "pop r23 \n\t" "pop r22 \n\t" "pop r21 \n\t" "pop r20 \n\t" "pop r19 \n\t" "pop r18 \n\t" ::); #endif } // // Interrupt handling // /* static */ inline void NewSoftSerial::handle_interrupts(int lopin, int hipin) { if (active_object && active_object->_receivePin >= lopin && active_object->_receivePin <= hipin) { active_object->recv(); } } ISR(PCINT0_vect) { NewSoftSerial::handle_interrupts(8, 13); } ISR(PCINT1_vect) { NewSoftSerial::handle_interrupts(14, 21); } ISR(PCINT2_vect) { NewSoftSerial::handle_interrupts(0, 7); } // // Constructor // NewSoftSerial::NewSoftSerial(uint8_t receivePin, uint8_t transmitPin) : _rx_delay_centering(0), _rx_delay_intrabit(0), _rx_delay_stopbit(0), _tx_delay(0), _buffer_overflow(false) { setTX(transmitPin); setRX(receivePin); } // // Public methods // void NewSoftSerial::setTX(uint8_t tx) { _transmitPin = tx; pinMode(_transmitPin, OUTPUT); digitalWrite(_transmitPin, HIGH); } void NewSoftSerial::setRX(uint8_t rx) { _receivePin = rx; pinMode(_receivePin, INPUT); digitalWrite(_receivePin, HIGH); // pullup! } void NewSoftSerial::begin(long speed) { _rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay = 0; for (unsigned i=0; i<sizeof(table)/sizeof(table[0]); ++i) { long baud = pgm_read_dword(&table[i].baud); if (baud == speed) { _rx_delay_centering = pgm_read_word(&table[i].rx_delay_centering); _rx_delay_intrabit = pgm_read_word(&table[i].rx_delay_intrabit); _rx_delay_stopbit = pgm_read_word(&table[i].rx_delay_stopbit);