mirror of https://github.com/arendst/Tasmota.git
84 lines
2.4 KiB
C++
84 lines
2.4 KiB
C++
/*
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pwm.c - analogWrite implementation for esp8266
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Use the shared TIMER1 utilities to generate PWM signals
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Original Copyright (c) 2015 Hristo Gochkov. All rights reserved.
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This file is part of the esp8266 core for Arduino environment.
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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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*/
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#ifdef ESP8266
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#include <Arduino.h>
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#include "core_esp8266_waveform.h"
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extern "C" {
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static uint32_t analogMap = 0;
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static int32_t analogScale = PWMRANGE;
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static uint16_t analogFreq = 1000;
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extern void __analogWriteRange(uint32_t range) {
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if (range > 0) {
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analogScale = range;
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}
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}
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extern void __analogWriteFreq(uint32_t freq) {
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if (freq < 40) {
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analogFreq = 40;
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} else if (freq > 60000) {
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analogFreq = 60000;
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} else {
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analogFreq = freq;
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}
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}
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extern void __analogWrite(uint8_t pin, int val) {
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if (pin > 16) {
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return;
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}
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uint32_t analogPeriod = microsecondsToClockCycles(1000000UL) / analogFreq;
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if (val < 0) {
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val = 0;
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} else if (val > analogScale) {
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val = analogScale;
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}
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if (analogMap & 1UL << pin) {
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analogMap &= ~(1 << pin);
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}
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else {
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pinMode(pin, OUTPUT);
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}
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uint32_t high = (analogPeriod * val) / analogScale;
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uint32_t low = analogPeriod - high;
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// Find the first GPIO being generated by checking GCC's find-first-set (returns 1 + the bit of the first 1 in an int32_t)
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int phaseReference = __builtin_ffs(analogMap) - 1;
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if (startWaveformClockCycles(pin, high, low, 0, phaseReference, 0, true)) {
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analogMap |= (1 << pin);
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}
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}
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extern void analogWrite(uint8_t pin, int val) __attribute__((weak, alias("__analogWrite")));
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extern void analogWriteFreq(uint32_t freq) __attribute__((weak, alias("__analogWriteFreq")));
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extern void analogWriteRange(uint32_t range) __attribute__((weak, alias("__analogWriteRange")));
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};
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#endif // ESP8266
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