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151 lines
4.2 KiB
151 lines
4.2 KiB
/*
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MD_REncoder - Library for Rotary Encoders
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See header file for comments
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This version copyright (C) 2014 Marco Colli. All rights reserved.
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Original library copyright 2011 Ben Buxton. Licenced under the GNU GPL Version 3.
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Contact: bb@cactii.net
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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 3 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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*/
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/**
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* \file
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* \brief Implements core MD_REncoder class methods
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*/
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#include <MD_REncoder.h>
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/*
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* The below state table has, for each state (row), the new state
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* to set based on the next encoder output. From left to right in,
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* the table, the encoder outputs are 00, 01, 10, 11, and the value
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* in that position is the new state to set.
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*/
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#define R_START 0x0
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#if ENABLE_HALF_STEP
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// Use the half-step state table (emits a code at 00 and 11)
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#define R_CCW_BEGIN 0x1
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#define R_CW_BEGIN 0x2
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#define R_START_M 0x3
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#define R_CW_BEGIN_M 0x4
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#define R_CCW_BEGIN_M 0x5
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const unsigned char ttable[][4] =
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{
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// 00 01 10 11
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{R_START_M, R_CW_BEGIN, R_CCW_BEGIN, R_START}, // R_START (00)
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{R_START_M | DIR_CCW, R_START, R_CCW_BEGIN, R_START}, // R_CCW_BEGIN
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{R_START_M | DIR_CW, R_CW_BEGIN, R_START, R_START}, // R_CW_BEGIN
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{R_START_M, R_CCW_BEGIN_M, R_CW_BEGIN_M, R_START}, // R_START_M (11)
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{R_START_M, R_START_M, R_CW_BEGIN_M, R_START | DIR_CW}, // R_CW_BEGIN_M
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{R_START_M, R_CCW_BEGIN_M, R_START_M, R_START | DIR_CCW} // R_CCW_BEGIN_M
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};
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#else
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// Use the full-step state table (emits a code at 00 only)
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#define R_CW_FINAL 0x1
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#define R_CW_BEGIN 0x2
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#define R_CW_NEXT 0x3
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#define R_CCW_BEGIN 0x4
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#define R_CCW_FINAL 0x5
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#define R_CCW_NEXT 0x6
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const unsigned char ttable[][4] =
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{
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// 00 01 10 11
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{R_START, R_CW_BEGIN, R_CCW_BEGIN, R_START}, // R_START
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{R_CW_NEXT, R_START, R_CW_FINAL, R_START | DIR_CW}, // R_CW_FINAL
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{R_CW_NEXT, R_CW_BEGIN, R_START, R_START}, // R_CW_BEGIN
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{R_CW_NEXT, R_CW_BEGIN, R_CW_FINAL, R_START}, // R_CW_NEXT
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{R_CCW_NEXT, R_START, R_CCW_BEGIN, R_START}, // R_CCW_BEGIN
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{R_CCW_NEXT, R_CCW_FINAL, R_START, R_START | DIR_CCW}, // R_CCW_FINAL
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{R_CCW_NEXT, R_CCW_FINAL, R_CCW_BEGIN, R_START} // R_CCW_NEXT
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};
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#endif
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MD_REncoder::MD_REncoder(uint8_t pinA, uint8_t pinB):
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_pinA (pinA), _pinB (pinB), _state(R_START)
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#if ENABLE_SPEED
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, _period(DEFAULT_PERIOD), _count(0), _spd(0), _timeLast(0)
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#endif
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{
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}
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void MD_REncoder::begin(void)
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{
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pinMode(_pinA, (ENABLE_PULLUPS ? INPUT_PULLUP : INPUT));
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pinMode(_pinB, (ENABLE_PULLUPS ? INPUT_PULLUP : INPUT));
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value=0;
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last_dir=DIR_NONE;
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}
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void MD_REncoder::update(void)
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// Grab state of input pins, determine new state from the pins
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// and state table, and return the emit bits (ie the generated event).
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{
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uint8_t pinstate = (digitalRead(_pinB) << 1) | digitalRead(_pinA);
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_state = ttable[_state & 0xf][pinstate];
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#if ENABLE_SPEED
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// handle the encoder velocity calc
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if (_state & 0x30) _count++;
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if (millis() - _timeLast >= _period)
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{
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_spd = _count * (1000/_period);
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_timeLast = millis();
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_count = 0;
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}
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#endif
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switch(_state & 0x30)
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{
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case DIR_CW:
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value++;
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last_dir=DIR_CW;
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break;
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case DIR_CCW:
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last_dir=DIR_CCW;
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value--;
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break;
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}
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}
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int32_t MD_REncoder::read_value(void)
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{
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return (value);
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}
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int8_t MD_REncoder::read(void)
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{
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switch(last_dir)
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{
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case DIR_CW:
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last_dir=DIR_NONE;
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return(4);
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case DIR_CCW:
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last_dir=DIR_NONE;
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return(-4);
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}
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return(0);
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}
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void MD_REncoder::write(int32_t v)
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{
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value=v;
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}
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