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Allow waveforms to be specified in clock cycles (#7211)

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* Allow waveforms to be specified in clock cycles

Allow the PWM to specify sub-microsecond waveform edges, as have been
proposed by @dok-net and me.  No other changes intended.

This will increase the linearity at 30 and 40 kHZ PWM rates, but leave
most other things unaffected.

* Cycle-accurate wafveform to specify Tone periods

Co-authored-by: Develo <deveyes@gmail.com>
This commit is contained in:
Earle F. Philhower, III 2020-04-16 14:40:20 -07:00 committed by GitHub
parent 6cb16997d8
commit 1af4ea661f
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 20 additions and 12 deletions
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11
cores/esp8266/Tone.cpp
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@ -22,6 +22,7 @@
*/
#include "Arduino.h"
#include "user_interface.h"
#include "core_esp8266_waveform.h"
// Which pins have a tone running on them?
@ -35,10 +36,10 @@ static void _startTone(uint8_t _pin, uint32_t high, uint32_t low, unsigned long
pinMode(_pin, OUTPUT);
high = std::max(high, (uint32_t)25); // new 20KHz maximum tone frequency,
low = std::max(low, (uint32_t)25); // (25us high + 25us low period = 20KHz)
high = std::max(high, (uint32_t)microsecondsToClockCycles(25)); // new 20KHz maximum tone frequency,
low = std::max(low, (uint32_t)microsecondsToClockCycles(25)); // (25us high + 25us low period = 20KHz)
if (startWaveform(_pin, high, low, (uint32_t) duration * 1000)) {
if (startWaveformCycles(_pin, high, low, microsecondsToClockCycles(duration * 1000))) {
_toneMap |= 1 << _pin;
}
}
@ -48,7 +49,7 @@ void tone(uint8_t _pin, unsigned int frequency, unsigned long duration) {
if (frequency == 0) {
noTone(_pin);
} else {
uint32_t period = 1000000L / frequency;
uint32_t period = (1000000L * system_get_cpu_freq()) / frequency;
uint32_t high = period / 2;
uint32_t low = period - high;
_startTone(_pin, high, low, duration);
@ -62,7 +63,7 @@ void tone(uint8_t _pin, double frequency, unsigned long duration) {
if (frequency < 1.0) { // FP means no exact comparisons
noTone(_pin);
} else {
double period = 1000000.0 / frequency;
double period = (1000000.0L * system_get_cpu_freq()) / frequency;
uint32_t high = (uint32_t)((period / 2.0) + 0.5);
uint32_t low = (uint32_t)(period + 0.5) - high;
_startTone(_pin, high, low, duration);

14
cores/esp8266/core_esp8266_waveform.cpp
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@ -112,15 +112,19 @@ void setTimer1Callback(uint32_t (*fn)()) {
// waveform smoothly on next low->high transition. For immediate change, stopWaveform()
// first, then it will immediately begin.
int startWaveform(uint8_t pin, uint32_t timeHighUS, uint32_t timeLowUS, uint32_t runTimeUS) {
if ((pin > 16) || isFlashInterfacePin(pin)) {
return startWaveformCycles(pin, microsecondsToClockCycles(timeHighUS), microsecondsToClockCycles(timeLowUS), microsecondsToClockCycles(runTimeUS));
}
int startWaveformCycles(uint8_t pin, uint32_t timeHighCycles, uint32_t timeLowCycles, uint32_t runTimeCycles) {
if ((pin > 16) || isFlashInterfacePin(pin)) {
return false;
}
Waveform *wave = &waveform[pin];
// Adjust to shave off some of the IRQ time, approximately
wave->nextTimeHighCycles = microsecondsToClockCycles(timeHighUS);
wave->nextTimeLowCycles = microsecondsToClockCycles(timeLowUS);
wave->expiryCycle = runTimeUS ? GetCycleCount() + microsecondsToClockCycles(runTimeUS) : 0;
if (runTimeUS && !wave->expiryCycle) {
wave->nextTimeHighCycles = timeHighCycles;
wave->nextTimeLowCycles = timeLowCycles;
wave->expiryCycle = runTimeCycles ? GetCycleCount() + runTimeCycles : 0;
if (runTimeCycles && !wave->expiryCycle) {
wave->expiryCycle = 1; // expiryCycle==0 means no timeout, so avoid setting it
}

2
cores/esp8266/core_esp8266_waveform.h
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@ -50,6 +50,8 @@ extern "C" {
// If runtimeUS > 0 then automatically stop it after that many usecs.
// Returns true or false on success or failure.
int startWaveform(uint8_t pin, uint32_t timeHighUS, uint32_t timeLowUS, uint32_t runTimeUS);
// Same as above, but pass in CPU clock cycles instead of microseconds
int startWaveformCycles(uint8_t pin, uint32_t timeHighCycles, uint32_t timeLowCycles, uint32_t runTimeCycles);
// Stop a waveform, if any, on the specified pin.
// Returns true or false on success or failure.
int stopWaveform(uint8_t pin);

5
cores/esp8266/core_esp8266_wiring_pwm.cpp
View File

@ -25,6 +25,7 @@
#include "core_esp8266_waveform.h"
extern "C" {
#include "user_interface.h"
static uint32_t analogMap = 0;
static int32_t analogScale = PWMRANGE;
@ -50,7 +51,7 @@ extern void __analogWrite(uint8_t pin, int val) {
if (pin > 16) {
return;
}
uint32_t analogPeriod = 1000000L / analogFreq;
uint32_t analogPeriod = (1000000L * system_get_cpu_freq()) / analogFreq;
if (val < 0) {
val = 0;
} else if (val > analogScale) {
@ -68,7 +69,7 @@ extern void __analogWrite(uint8_t pin, int val) {
stopWaveform(pin);
digitalWrite(pin, LOW);
} else {
if (startWaveform(pin, high, low, 0)) {
if (startWaveformCycles(pin, high, low, 0)) {
analogMap |= (1 << pin);
}
}