From 8014ccc1356eec141042c8fe367f9d78d5ff76d2 Mon Sep 17 00:00:00 2001
From: "Dirk O. Kaar" <dok@dok-net.net>
Date: Mon, 12 Apr 2021 20:41:34 +0200
Subject: [PATCH 1/3] Library was overlooked in "PWM-locked" / "phase-locked"
 waveform mode merge.

---
 libraries/Servo/src/Servo.cpp | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/libraries/Servo/src/Servo.cpp b/libraries/Servo/src/Servo.cpp
index d24ea33799..d2594eee1c 100644
--- a/libraries/Servo/src/Servo.cpp
+++ b/libraries/Servo/src/Servo.cpp
@@ -69,13 +69,8 @@ uint8_t Servo::attach(int pin, uint16_t minUs, uint16_t maxUs)
 uint8_t Servo::attach(int pin, uint16_t minUs, uint16_t maxUs, int value)
 {
   if (!_attached) {
-#ifdef WAVEFORM_LOCKED_PHASE
     pinMode(pin, OUTPUT);
     digitalWrite(pin, LOW);
-#else
-    digitalWrite(pin, LOW);
-    pinMode(pin, OUTPUT);
-#endif
     _pin = pin;
     _attached = true;
   }
@@ -95,11 +90,8 @@ void Servo::detach()
 {
   if (_attached) {
     _servoMap &= ~(1 << _pin);
-#ifdef WAVEFORM_LOCKED_PHASE
+    // TODO - timeHigh == 0 is illegal in _PWM code branch. And now what?
     startWaveform(_pin, 0, REFRESH_INTERVAL, 1);
-#else
-    // TODO - timeHigh == 0 is illegal in _PWM code branch.  Do nothing for now.
-#endif
     delay(REFRESH_INTERVAL / 1000); // long enough to complete active period under all circumstances.
     stopWaveform(_pin);
     _attached = false;
@@ -124,13 +116,9 @@ void Servo::writeMicroseconds(int value)
   _valueUs = value;
   if (_attached) {
     _servoMap &= ~(1 << _pin);
-#ifdef WAVEFORM_LOCKED_PHASE
     // 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)
     int phaseReference = __builtin_ffs(_servoMap) - 1;
     if (startWaveform(_pin, _valueUs, REFRESH_INTERVAL - _valueUs, 0, phaseReference))
-#else
-    if (startWaveform(_pin, _valueUs, REFRESH_INTERVAL - _valueUs, 0))
-#endif
     {
       _servoMap |= (1 << _pin);
     }

From 21fc5fbd9b2e4369abea45ec6508d61f680759ff Mon Sep 17 00:00:00 2001
From: "Dirk O. Kaar" <dok@dok-net.net>
Date: Fri, 16 Apr 2021 09:38:48 +0200
Subject: [PATCH 2/3] Per review.

---
 cores/esp8266/core_esp8266_waveform_pwm.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cores/esp8266/core_esp8266_waveform_pwm.cpp b/cores/esp8266/core_esp8266_waveform_pwm.cpp
index b33a657ba1..2107ef726c 100644
--- a/cores/esp8266/core_esp8266_waveform_pwm.cpp
+++ b/cores/esp8266/core_esp8266_waveform_pwm.cpp
@@ -356,7 +356,7 @@ int startWaveformClockCycles_weak(uint8_t pin, uint32_t timeHighCycles, uint32_t
   (void) phaseOffsetUS;
   (void) autoPwm;
 
-   if ((pin > 16) || isFlashInterfacePin(pin)) {
+   if ((pin > 16) || isFlashInterfacePin(pin) || (timeHighCycles == 0)) {
     return false;
   }
   Waveform *wave = &wvfState.waveform[pin];

From e772aba090eae6ca535a94db3cc650af32a5c07e Mon Sep 17 00:00:00 2001
From: "Dirk O. Kaar" <dok@dok-net.net>
Date: Fri, 16 Apr 2021 21:11:07 +0200
Subject: [PATCH 3/3] Drop resolved TODO

---
 libraries/Servo/src/Servo.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/libraries/Servo/src/Servo.cpp b/libraries/Servo/src/Servo.cpp
index d2594eee1c..2c21524822 100644
--- a/libraries/Servo/src/Servo.cpp
+++ b/libraries/Servo/src/Servo.cpp
@@ -90,7 +90,6 @@ void Servo::detach()
 {
   if (_attached) {
     _servoMap &= ~(1 << _pin);
-    // TODO - timeHigh == 0 is illegal in _PWM code branch. And now what?
     startWaveform(_pin, 0, REFRESH_INTERVAL, 1);
     delay(REFRESH_INTERVAL / 1000); // long enough to complete active period under all circumstances.
     stopWaveform(_pin);