diff --git a/cores/esp8266/Arduino.h b/cores/esp8266/Arduino.h index b484a3765..2aab5770c 100644 --- a/cores/esp8266/Arduino.h +++ b/cores/esp8266/Arduino.h @@ -171,6 +171,7 @@ int digitalRead(uint8_t pin); int analogRead(uint8_t pin); void analogReference(uint8_t mode); void analogWrite(uint8_t pin, int val); +void analogWriteMode(uint8_t pin, int val, bool openDrain); void analogWriteFreq(uint32_t freq); void analogWriteResolution(int res); void analogWriteRange(uint32_t range); diff --git a/cores/esp8266/core_esp8266_wiring_pwm.cpp b/cores/esp8266/core_esp8266_wiring_pwm.cpp index f730f649e..5bd5416d7 100644 --- a/cores/esp8266/core_esp8266_wiring_pwm.cpp +++ b/cores/esp8266/core_esp8266_wiring_pwm.cpp @@ -44,6 +44,10 @@ extern void __analogWriteFreq(uint32_t freq) { } extern void __analogWrite(uint8_t pin, int val) { + analogWriteMode(pin, val, false); +} + +extern void __analogWriteMode(uint8_t pin, int val, bool openDrain) { if (pin > 16) { return; } @@ -62,7 +66,11 @@ extern void __analogWrite(uint8_t pin, int val) { analogMap &= ~(1 << pin); } else { - pinMode(pin, OUTPUT); + if(openDrain) { + pinMode(pin, OUTPUT_OPEN_DRAIN); + } else { + pinMode(pin, OUTPUT); + } } uint32_t high = (analogPeriod * val) / analogScale; uint32_t low = analogPeriod - high; @@ -88,6 +96,7 @@ extern void __analogWriteResolution(int res) { } extern void analogWrite(uint8_t pin, int val) __attribute__((weak, alias("__analogWrite"))); +extern void analogWriteMode(uint8_t pin, int val, bool openDrain) __attribute__((weak, alias("__analogWriteMode"))); extern void analogWriteFreq(uint32_t freq) __attribute__((weak, alias("__analogWriteFreq"))); extern void analogWriteRange(uint32_t range) __attribute__((weak, alias("__analogWriteRange"))); extern void analogWriteResolution(int res) __attribute__((weak, alias("__analogWriteResolution"))); diff --git a/doc/reference.rst b/doc/reference.rst index 2ae8ca5cd..32f5987f8 100644 --- a/doc/reference.rst +++ b/doc/reference.rst @@ -109,6 +109,9 @@ PWM range may be changed by calling ``analogWriteRange(new_range)`` or ``analogWriteResolution(bits)``. ``new_range`` may be from 15...65535 or ``bits`` may be from 4...16. +The function ``analogWriteMode(pin, value, openDrain)`` allows to sets +the pin mode to ``OUTPUT_OPEN_DRAIN`` instead of ``OUTPUT``. + **NOTE:** The default ``analogWrite`` range was 1023 in releases before 3.0, but this lead to incompatibility with external libraries which depended on the Arduino core default of 256. Existing applications which