mirror of https://github.com/arendst/Tasmota.git
94 lines
4.3 KiB
C
94 lines
4.3 KiB
C
/*
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esp8266_waveform - General purpose waveform generation and control,
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supporting outputs on all pins in parallel.
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Copyright (c) 2018 Earle F. Philhower, III. All rights reserved.
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Copyright (c) 2020 Dirk O. Kaar.
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The core idea is to have a programmable waveform generator with a unique
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high and low period (defined in microseconds or CPU clock cycles). TIMER1 is
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set to 1-shot mode and is always loaded with the time until the next edge
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of any live waveforms.
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Up to one waveform generator per pin supported.
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Each waveform generator is synchronized to the ESP clock cycle counter, not the
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timer. This allows for removing interrupt jitter and delay as the counter
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always increments once per 80MHz clock. Changes to a waveform are
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contiguous and only take effect on the next waveform transition,
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allowing for smooth transitions.
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This replaces older tone(), analogWrite(), and the Servo classes.
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Everywhere in the code where "ccy" or "ccys" is used, it means ESP.getCycleCount()
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clock cycle count, or an interval measured in CPU clock cycles, but not TIMER1
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cycles (which may be 2 CPU clock cycles @ 160MHz).
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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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#ifndef __ESP8266_WAVEFORM_H
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#define __ESP8266_WAVEFORM_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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// Start or change a waveform of the specified high and low times on specific pin.
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// If runtimeUS > 0 then automatically stop it after that many usecs, relative to the next
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// full period.
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// If waveform is not yet started on pin, and on pin == alignPhase a waveform is running,
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// the new waveform is started at phaseOffsetUS phase offset, in microseconds, to that.
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// Setting autoPwm to true allows the wave generator to maintain PWM duty to idle cycle ratio
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// under load, for applications where frequency or duty cycle must not change, leave false.
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// Returns true or false on success or failure.
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int startWaveform(uint8_t pin, uint32_t timeHighUS, uint32_t timeLowUS,
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uint32_t runTimeUS = 0, int8_t alignPhase = -1, uint32_t phaseOffsetUS = 0, bool autoPwm = false);
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// Start or change a waveform of the specified high and low CPU clock cycles on specific pin.
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// If runtimeCycles > 0 then automatically stop it after that many CPU clock cycles, relative to the next
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// full period.
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// If waveform is not yet started on pin, and on pin == alignPhase a waveform is running,
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// the new waveform is started at phaseOffsetCcys phase offset, in CPU clock cycles, to that.
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// Setting autoPwm to true allows the wave generator to maintain PWM duty to idle cycle ratio
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// under load, for applications where frequency or duty cycle must not change, leave false.
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// Returns true or false on success or failure.
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int startWaveformClockCycles(uint8_t pin, uint32_t timeHighCcys, uint32_t timeLowCcys,
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uint32_t runTimeCcys = 0, int8_t alignPhase = -1, uint32_t phaseOffsetCcys = 0, bool autoPwm = false);
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// Stop a waveform, if any, on the specified pin.
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// Returns true or false on success or failure.
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int stopWaveform(uint8_t pin);
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// Add a callback function to be called on *EVERY* timer1 trigger. The
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// callback returns the number of microseconds until the next desired call.
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// However, since it is called every timer1 interrupt, it may be called
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// again before this period. It should therefore use the ESP Cycle Counter
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// to determine whether or not to perform an operation.
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// Pass in NULL to disable the callback and, if no other waveforms being
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// generated, stop the timer as well.
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// Make sure the CB function has the ICACHE_RAM_ATTR decorator.
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void setTimer1Callback(uint32_t (*fn)());
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#ifdef __cplusplus
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}
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#endif
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#endif
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#endif // ESP8266
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