From f2a1e107b9585d6a927471889f361965acdca748 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Fri, 25 Feb 2022 17:49:08 +0000
Subject: [PATCH 01/18] Add hardware PWM for fan & laser/spindle PWM

---
 Marlin/src/HAL/ESP32/HAL.cpp           | 116 +++++++++++++++++++------
 Marlin/src/HAL/ESP32/HAL.h             |  26 ++++--
 Marlin/src/HAL/ESP32/Servo.cpp         |  15 ++--
 Marlin/src/HAL/ESP32/Servo.h           |   3 +-
 Marlin/src/HAL/ESP32/inc/SanityCheck.h |   8 +-
 5 files changed, 121 insertions(+), 47 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index adf5cecabe41..155056b4129a 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -76,6 +76,9 @@ uint32_t thresholds[ADC_ATTEN_MAX];
 volatile int numPWMUsed = 0,
              pwmPins[MAX_PWM_PINS],
              pwmValues[MAX_PWM_PINS];
+pin_t chan_pin[CHANNEL_MAX_NUM + 1] = { 0 }; // PWM capable IOpins - not 0 or >33 on ESP32
+uint32_t chan_freq[(CHANNEL_MAX_NUM + 1) / 2]; // ledcReadFreq doesn't work if a duty hasn't been set yet!
+uint16_t chan_res[(CHANNEL_MAX_NUM + 1) / 2];
 
 // ------------------------
 // Public functions
@@ -248,42 +251,99 @@ void MarlinHAL::adc_start(const pin_t pin) {
   adc1_set_attenuation(chan, atten);
 }
 
-void analogWrite(pin_t pin, int value) {
+// ------------------------
+// PWM
+// ------------------------
+
+int8_t pin_to_chan(uint8_t pin) {
+	for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
+		if (chan_pin[i] == pin) return i;
+	}
+	return -1;
+}
+
+// get PWM channel for pin - if none then attach a new one
+// return -1 if fail or invalid pin#, channel # (0-15) if success
+int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res) {
+	if (pin == 0 || (pin > MAX_PWM_IOPIN)) return -1;     // not a hardware PWM pin!
+	int8_t chan = pin_to_chan(pin);
+	if (chan >= 0) return chan;
+
+	// find an empty adjacent chanel (same timer & freq/res)
+	for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
+		if (chan_pin[i] == 0) {
+			if (chan_pin[i ^ 0x1] != 0) {
+				if ((chan_freq[i / 2] == freq) && (chan_res[i / 2] == res)) {
+					chan_pin[i] = pin; // allocate pwm to this channel
+					ledcAttachPin(pin, i);
+					return i;
+				}
+			}
+			else if (chan == -1) { // pair of empty channels?
+				chan = i & 0xfe; // save lower channel number
+			}
+		}
+	}
+	// not attached, is an empty timer slot avail?
+	if (chan >= 0) {
+		chan_freq[chan / 2] = freq;
+		chan_pin[chan] = pin;
+		chan_res[chan / 2] = res;
+		ledcSetup(chan, freq, res);
+		ledcAttachPin(pin, chan);
+	}
+	return chan; // -1 if no channel avail
+}
+
+void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=_BV(PWM_RESOLUTION)-1*/, const bool invert/*=false*/) {
+	int8_t channel = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
+	if (channel >= 0) {
+		uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
+		ledcWrite(channel, duty);
+	}
+}
+
+uint8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
+	int8_t channel = pin_to_chan(pin);
+	if (channel >= 0) {
+		if (f_desired == ledcReadFreq(channel)) return channel; // no freq change 
+		ledcDetachPin(chan_pin[channel]);
+		chan_pin[channel] = 0;							// remove old freq channel
+	}
+	return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
+}
+
+// use hardware PWM if avail, if not then ISR
+void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PWM_FREQUENCY*/, const uint16_t res/*=8*/) { // always 8 bit resolution!
   // Use ledc hardware for internal pins
-  if (pin < 34) {
-    static int cnt_channel = 1, pin_to_channel[40] = { 0 };
-    if (pin_to_channel[pin] == 0) {
-      ledcAttachPin(pin, cnt_channel);
-      ledcSetup(cnt_channel, 490, 8);
-      ledcWrite(cnt_channel, value);
-      pin_to_channel[pin] = cnt_channel++;
-    }
-    ledcWrite(pin_to_channel[pin], value);
-    return;
+  int8_t channel = get_pwm_channel(pin, freq, res);
+  if (channel >= 0) {
+    ledcWrite(channel, value); // set duty value
   }
+  else { // not a hardware PWM pin OR no PWM channels available
+    int idx = -1;
 
-  int idx = -1;
+    // Search Pin
+    for (int i = 0; i < numPWMUsed; ++i)
+      if (pwmPins[i] == pin) { idx = i; break; }
 
-  // Search Pin
-  for (int i = 0; i < numPWMUsed; ++i)
-    if (pwmPins[i] == pin) { idx = i; break; }
+    // not found ?
+    if (idx < 0) {
+      // No slots remaining
+      if (numPWMUsed >= MAX_PWM_PINS) return;
 
-  // not found ?
-  if (idx < 0) {
-    // No slots remaining
-    if (numPWMUsed >= MAX_PWM_PINS) return;
+      // Take new slot for pin
+      idx = numPWMUsed;
+      pwmPins[idx] = pin;
+      // Start timer on first use
+      if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
 
-    // Take new slot for pin
-    idx = numPWMUsed;
-    pwmPins[idx] = pin;
-    // Start timer on first use
-    if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
+      ++numPWMUsed;
+    }
 
-    ++numPWMUsed;
+    // Use 7bit internal value - add 1 to have 100% high at 255
+    pwmValues[idx] = (value + 1) / 2;
   }
-
-  // Use 7bit internal value - add 1 to have 100% high at 255
-  pwmValues[idx] = (value + 1) / 2;
 }
 
 // Handle PWM timer interrupt
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index df52e2186cbd..9d9fe8526ff8 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -64,6 +64,12 @@
 #define CRITICAL_SECTION_START() portENTER_CRITICAL(&spinlock)
 #define CRITICAL_SECTION_END()   portEXIT_CRITICAL(&spinlock)
 
+#define HAL_CAN_SET_PWM_FREQ   // This HAL supports PWM Frequency adjustment
+#define PWM_FREQUENCY 1000u     // Default PWM frequency when set_pwm_duty() is called without set_pwm_frequency()
+#define PWM_RESOLUTION 10u 	   // Default PWM bit resolution
+#define CHANNEL_MAX_NUM 15u    // max PWM channel to allocate (7 to only use low speed, 15 to use high speed - see above)
+#define MAX_PWM_IOPIN 33u      // hardware pwm pins < 34
+
 // ------------------------
 // Types
 // ------------------------
@@ -83,7 +89,7 @@ typedef Servo hal_servo_t;
 void tone(const pin_t _pin, const unsigned int frequency, const unsigned long duration=0);
 void noTone(const pin_t _pin);
 
-void analogWrite(pin_t pin, int value);
+void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq=PWM_FREQUENCY, const uint16_t res=8);
 
 //
 // Pin Mapping for M42, M43, M226
@@ -208,13 +214,19 @@ class MarlinHAL {
   // The current value of the ADC register
   static uint16_t adc_value() { return adc_result; }
 
+   /**
+   * If not already allocated, allocate a hardware PWM channel
+   * to the pin and set the duty cycle..
+   * Optionally invert the duty cycle [default = false]
+   * Optionally change the scale of the provided value to enable finer PWM duty control [default = 255]
+   */
+  static void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size=255, const bool invert=false);
+
   /**
-   * Set the PWM duty cycle for the pin to the given value.
-   * No inverting the duty cycle in this HAL.
-   * No changing the maximum size of the provided value to enable finer PWM duty control in this HAL.
+   * Allocate and set the frequency of a hardware PWM pin
+   * Returns -1 if no pin available.
    */
-  static void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t=255, const bool=false) {
-    analogWrite(pin, v);
-  }
+  static uint8_t set_pwm_frequency(const pin_t pin, const uint32_t f_desired);
+
 
 };
diff --git a/Marlin/src/HAL/ESP32/Servo.cpp b/Marlin/src/HAL/ESP32/Servo.cpp
index fcf58485819e..79c0ce692ec5 100644
--- a/Marlin/src/HAL/ESP32/Servo.cpp
+++ b/Marlin/src/HAL/ESP32/Servo.cpp
@@ -32,19 +32,18 @@
 int Servo::channel_next_free = 12;
 
 Servo::Servo() {
-  channel = channel_next_free++;
 }
 
 int8_t Servo::attach(const int inPin) {
-  if (channel >= CHANNEL_MAX_NUM) return -1;
   if (inPin > 0) pin = inPin;
-
-  ledcSetup(channel, 50, 16); // channel X, 50 Hz, 16-bit depth
-  ledcAttachPin(pin, channel);
-  return true;
+	channel = get_pwm_channel(pin, 50u, 16u);
+  return channel; // -1 if no PWM avail.
 }
 
-void Servo::detach() { ledcDetachPin(pin); }
+// leave channel connected to servo - set duty to zero
+void Servo::detach() { 
+	if (channel != -1) ledcWrite(channel, 0);
+}
 
 int Servo::read() { return degrees; }
 
@@ -52,7 +51,7 @@ void Servo::write(int inDegrees) {
   degrees = constrain(inDegrees, MIN_ANGLE, MAX_ANGLE);
   int us = map(degrees, MIN_ANGLE, MAX_ANGLE, MIN_PULSE_WIDTH, MAX_PULSE_WIDTH);
   int duty = map(us, 0, TAU_USEC, 0, MAX_COMPARE);
-  ledcWrite(channel, duty);
+  if (channel >= 0) ledcWrite(channel, duty); // don't save duty for servos!
 }
 
 void Servo::move(const int value) {
diff --git a/Marlin/src/HAL/ESP32/Servo.h b/Marlin/src/HAL/ESP32/Servo.h
index 8542092d66ea..1dbb416a8317 100644
--- a/Marlin/src/HAL/ESP32/Servo.h
+++ b/Marlin/src/HAL/ESP32/Servo.h
@@ -30,8 +30,7 @@ class Servo {
                    MAX_PULSE_WIDTH = 2400,  // Longest pulse sent to a servo
                    TAU_MSEC = 20,
                    TAU_USEC = (TAU_MSEC * 1000),
-                   MAX_COMPARE = _BV(16) - 1, // 65535
-                   CHANNEL_MAX_NUM = 16;
+                   MAX_COMPARE = _BV(16) - 1; // 65535
 
 public:
   Servo();
diff --git a/Marlin/src/HAL/ESP32/inc/SanityCheck.h b/Marlin/src/HAL/ESP32/inc/SanityCheck.h
index 8bbc68d8715b..7af5d4b692dc 100644
--- a/Marlin/src/HAL/ESP32/inc/SanityCheck.h
+++ b/Marlin/src/HAL/ESP32/inc/SanityCheck.h
@@ -25,8 +25,12 @@
   #error "EMERGENCY_PARSER is not yet implemented for ESP32. Disable EMERGENCY_PARSER to continue."
 #endif
 
-#if ENABLED(FAST_PWM_FAN) || SPINDLE_LASER_FREQUENCY
-  #error "Features requiring Hardware PWM (FAST_PWM_FAN, SPINDLE_LASER_FREQUENCY) are not yet supported on ESP32."
+#if ENABLED(BOARD_MKS_TINYBEE) && ENABLED(FAST_PWM_FAN) 
+  #error "FAST_PWM_FAN not available on TinyBee."
+#endif
+  
+#if (ENABLED(SPINDLE_LASER_USE_PWM) && (SPINDLE_LASER_FREQUENCY > 78125)) || (ENABLED(FAST_PWM_FAN_FREQUENCY) && (FAST_PWM_FAN_FREQUENCY > 78125))
+  #error "SPINDLE_LASER_FREQUENCY and FAST_PWM_FREQUENCY maximum value is 78125Hz for ESP32."
 #endif
 
 #if HAS_TMC_SW_SERIAL

From 91b50879231412bc3ddaf9e3bc7a7abb2548c97d Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Fri, 25 Feb 2022 18:55:09 +0000
Subject: [PATCH 02/18] Delete duplicate code

---
 Marlin/src/HAL/ESP32/HAL.cpp | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 155056b4129a..29184298ce05 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -340,9 +340,6 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
 
       ++numPWMUsed;
     }
-
-    // Use 7bit internal value - add 1 to have 100% high at 255
-    pwmValues[idx] = (value + 1) / 2;
   }
 }
 

From 95a4e90d4b1ea6317cb0df1bc633e79d073f646d Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Fri, 25 Feb 2022 18:58:10 +0000
Subject: [PATCH 03/18] Replaced  deleted code

---
 Marlin/src/HAL/ESP32/HAL.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 29184298ce05..44426e746b1d 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -338,6 +338,8 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
       // Start timer on first use
       if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
 
+      // Use 7bit internal value - add 1 to have 100% high at 255
+      pwmValues[idx] = (value + 1) / 2;
       ++numPWMUsed;
     }
   }

From d3a3a8599a1eb1c2eb46b175ca8f26ca872e09ce Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Fri, 25 Feb 2022 19:02:09 +0000
Subject: [PATCH 04/18] Revert "Replaced  deleted code"

This reverts commit 95a4e90d4b1ea6317cb0df1bc633e79d073f646d.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 44426e746b1d..29184298ce05 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -338,8 +338,6 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
       // Start timer on first use
       if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
 
-      // Use 7bit internal value - add 1 to have 100% high at 255
-      pwmValues[idx] = (value + 1) / 2;
       ++numPWMUsed;
     }
   }

From e34268982b628bda30b5be2964ebc56100b9c269 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Fri, 25 Feb 2022 19:02:34 +0000
Subject: [PATCH 05/18] Revert "Delete duplicate code"

This reverts commit 91b50879231412bc3ddaf9e3bc7a7abb2548c97d.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 29184298ce05..155056b4129a 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -340,6 +340,9 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
 
       ++numPWMUsed;
     }
+
+    // Use 7bit internal value - add 1 to have 100% high at 255
+    pwmValues[idx] = (value + 1) / 2;
   }
 }
 

From 571e41bd1cb6352e322cb2ba58a5d7a3b6c8c2f4 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Sat, 26 Feb 2022 14:39:53 -0600
Subject: [PATCH 06/18] misc. cleanup

---
 Marlin/src/HAL/ESP32/HAL.cpp           | 87 +++++++++++++-------------
 Marlin/src/HAL/ESP32/HAL.h             | 11 ++--
 Marlin/src/HAL/ESP32/Servo.cpp         |  9 ++-
 Marlin/src/HAL/ESP32/inc/SanityCheck.h | 10 +--
 4 files changed, 57 insertions(+), 60 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 155056b4129a..e2b8f111bfd5 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -256,61 +256,60 @@ void MarlinHAL::adc_start(const pin_t pin) {
 // ------------------------
 
 int8_t pin_to_chan(uint8_t pin) {
-	for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
-		if (chan_pin[i] == pin) return i;
-	}
-	return -1;
+  for (int i = 0; i <= CHANNEL_MAX_NUM; i++)
+    if (chan_pin[i] == pin) return i;
+  return -1;
 }
 
 // get PWM channel for pin - if none then attach a new one
 // return -1 if fail or invalid pin#, channel # (0-15) if success
 int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res) {
-	if (pin == 0 || (pin > MAX_PWM_IOPIN)) return -1;     // not a hardware PWM pin!
-	int8_t chan = pin_to_chan(pin);
-	if (chan >= 0) return chan;
-
-	// find an empty adjacent chanel (same timer & freq/res)
-	for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
-		if (chan_pin[i] == 0) {
-			if (chan_pin[i ^ 0x1] != 0) {
-				if ((chan_freq[i / 2] == freq) && (chan_res[i / 2] == res)) {
-					chan_pin[i] = pin; // allocate pwm to this channel
-					ledcAttachPin(pin, i);
-					return i;
-				}
-			}
-			else if (chan == -1) { // pair of empty channels?
-				chan = i & 0xfe; // save lower channel number
-			}
-		}
-	}
-	// not attached, is an empty timer slot avail?
-	if (chan >= 0) {
-		chan_freq[chan / 2] = freq;
-		chan_pin[chan] = pin;
-		chan_res[chan / 2] = res;
-		ledcSetup(chan, freq, res);
-		ledcAttachPin(pin, chan);
-	}
-	return chan; // -1 if no channel avail
+  if (pin == 0 || (pin > MAX_PWM_IOPIN)) return -1;     // not a hardware PWM pin!
+  int8_t chan = pin_to_chan(pin);
+  if (chan >= 0) return chan;
+
+  // find an empty adjacent chanel (same timer & freq/res)
+  for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
+    if (chan_pin[i] == 0) {
+      if (chan_pin[i ^ 0x1] != 0) {
+        if ((chan_freq[i / 2] == freq) && (chan_res[i / 2] == res)) {
+          chan_pin[i] = pin; // allocate pwm to this channel
+          ledcAttachPin(pin, i);
+          return i;
+        }
+      }
+      else if (chan == -1) { // pair of empty channels?
+        chan = i & 0xfe; // save lower channel number
+      }
+    }
+  }
+  // not attached, is an empty timer slot avail?
+  if (chan >= 0) {
+    chan_freq[chan / 2] = freq;
+    chan_pin[chan] = pin;
+    chan_res[chan / 2] = res;
+    ledcSetup(chan, freq, res);
+    ledcAttachPin(pin, chan);
+  }
+  return chan; // -1 if no channel avail
 }
 
 void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=_BV(PWM_RESOLUTION)-1*/, const bool invert/*=false*/) {
-	int8_t channel = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
-	if (channel >= 0) {
-		uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
-		ledcWrite(channel, duty);
-	}
+  int8_t channel = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
+  if (channel >= 0) {
+    uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
+    ledcWrite(channel, duty);
+  }
 }
 
 uint8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
-	int8_t channel = pin_to_chan(pin);
-	if (channel >= 0) {
-		if (f_desired == ledcReadFreq(channel)) return channel; // no freq change 
-		ledcDetachPin(chan_pin[channel]);
-		chan_pin[channel] = 0;							// remove old freq channel
-	}
-	return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
+  int8_t channel = pin_to_chan(pin);
+  if (channel >= 0) {
+    if (f_desired == ledcReadFreq(channel)) return channel; // no freq change
+    ledcDetachPin(chan_pin[channel]);
+    chan_pin[channel] = 0;              // remove old freq channel
+  }
+  return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
 }
 
 // use hardware PWM if avail, if not then ISR
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index 9d9fe8526ff8..f37dd62a8688 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -65,10 +65,10 @@
 #define CRITICAL_SECTION_END()   portEXIT_CRITICAL(&spinlock)
 
 #define HAL_CAN_SET_PWM_FREQ   // This HAL supports PWM Frequency adjustment
-#define PWM_FREQUENCY 1000u     // Default PWM frequency when set_pwm_duty() is called without set_pwm_frequency()
-#define PWM_RESOLUTION 10u 	   // Default PWM bit resolution
-#define CHANNEL_MAX_NUM 15u    // max PWM channel to allocate (7 to only use low speed, 15 to use high speed - see above)
-#define MAX_PWM_IOPIN 33u      // hardware pwm pins < 34
+#define PWM_FREQUENCY  1000u   // Default PWM frequency when set_pwm_duty() is called without set_pwm_frequency()
+#define PWM_RESOLUTION   10u   // Default PWM bit resolution
+#define CHANNEL_MAX_NUM  15u   // max PWM channel to allocate (7 to only use low speed, 15 to use high speed - see above)
+#define MAX_PWM_IOPIN    33u   // hardware pwm pins < 34
 
 // ------------------------
 // Types
@@ -214,7 +214,7 @@ class MarlinHAL {
   // The current value of the ADC register
   static uint16_t adc_value() { return adc_result; }
 
-   /**
+  /**
    * If not already allocated, allocate a hardware PWM channel
    * to the pin and set the duty cycle..
    * Optionally invert the duty cycle [default = false]
@@ -228,5 +228,4 @@ class MarlinHAL {
    */
   static uint8_t set_pwm_frequency(const pin_t pin, const uint32_t f_desired);
 
-
 };
diff --git a/Marlin/src/HAL/ESP32/Servo.cpp b/Marlin/src/HAL/ESP32/Servo.cpp
index 79c0ce692ec5..de72b7110480 100644
--- a/Marlin/src/HAL/ESP32/Servo.cpp
+++ b/Marlin/src/HAL/ESP32/Servo.cpp
@@ -31,18 +31,17 @@
 // so we only allocate servo channels up high to avoid side effects with regards to analogWrite (fans, leds, laser pwm etc.)
 int Servo::channel_next_free = 12;
 
-Servo::Servo() {
-}
+Servo::Servo() {}
 
 int8_t Servo::attach(const int inPin) {
   if (inPin > 0) pin = inPin;
-	channel = get_pwm_channel(pin, 50u, 16u);
+  channel = get_pwm_channel(pin, 50u, 16u);
   return channel; // -1 if no PWM avail.
 }
 
 // leave channel connected to servo - set duty to zero
-void Servo::detach() { 
-	if (channel != -1) ledcWrite(channel, 0);
+void Servo::detach() {
+  if (channel != -1) ledcWrite(channel, 0);
 }
 
 int Servo::read() { return degrees; }
diff --git a/Marlin/src/HAL/ESP32/inc/SanityCheck.h b/Marlin/src/HAL/ESP32/inc/SanityCheck.h
index 7af5d4b692dc..052c7e9d12fe 100644
--- a/Marlin/src/HAL/ESP32/inc/SanityCheck.h
+++ b/Marlin/src/HAL/ESP32/inc/SanityCheck.h
@@ -25,11 +25,7 @@
   #error "EMERGENCY_PARSER is not yet implemented for ESP32. Disable EMERGENCY_PARSER to continue."
 #endif
 
-#if ENABLED(BOARD_MKS_TINYBEE) && ENABLED(FAST_PWM_FAN) 
-  #error "FAST_PWM_FAN not available on TinyBee."
-#endif
-  
-#if (ENABLED(SPINDLE_LASER_USE_PWM) && (SPINDLE_LASER_FREQUENCY > 78125)) || (ENABLED(FAST_PWM_FAN_FREQUENCY) && (FAST_PWM_FAN_FREQUENCY > 78125))
+#if (ENABLED(SPINDLE_LASER_USE_PWM) && SPINDLE_LASER_FREQUENCY > 78125) || (ENABLED(FAST_PWM_FAN_FREQUENCY) && FAST_PWM_FAN_FREQUENCY > 78125)
   #error "SPINDLE_LASER_FREQUENCY and FAST_PWM_FREQUENCY maximum value is 78125Hz for ESP32."
 #endif
 
@@ -44,3 +40,7 @@
 #if ENABLED(POSTMORTEM_DEBUGGING)
   #error "POSTMORTEM_DEBUGGING is not yet supported on ESP32."
 #endif
+
+#if MB(MKS_TINYBEE) && ENABLED(FAST_PWM_FAN)
+  #error "FAST_PWM_FAN is not available on TinyBee."
+#endif

From c2b1e3ae7bc2551ba6bdfd21d40912e94c300db6 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Sat, 26 Feb 2022 14:49:43 -0600
Subject: [PATCH 07/18] use structs, replace WRITE

---
 Marlin/src/HAL/ESP32/HAL.cpp   | 88 +++++++++++++++++-----------------
 Marlin/src/HAL/ESP32/HAL.h     |  2 +-
 Marlin/src/HAL/ESP32/Servo.cpp |  2 +-
 3 files changed, 47 insertions(+), 45 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index e2b8f111bfd5..76037e372386 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -73,12 +73,15 @@ uint16_t MarlinHAL::adc_result;
 esp_adc_cal_characteristics_t characteristics[ADC_ATTEN_MAX];
 adc_atten_t attenuations[ADC1_CHANNEL_MAX] = {};
 uint32_t thresholds[ADC_ATTEN_MAX];
-volatile int numPWMUsed = 0,
-             pwmPins[MAX_PWM_PINS],
-             pwmValues[MAX_PWM_PINS];
-pin_t chan_pin[CHANNEL_MAX_NUM + 1] = { 0 }; // PWM capable IOpins - not 0 or >33 on ESP32
-uint32_t chan_freq[(CHANNEL_MAX_NUM + 1) / 2]; // ledcReadFreq doesn't work if a duty hasn't been set yet!
-uint16_t chan_res[(CHANNEL_MAX_NUM + 1) / 2];
+
+volatile int numPWMUsed = 0;
+volatile struct { pin_t pin; int value; } pwmInfo[MAX_PWM_PINS];
+
+struct {
+  pin_t    pin;  // PWM capable IOpins - not 0 or >33 on ESP32
+  uint32_t freq; // ledcReadFreq doesn't work if a duty hasn't been set yet!
+  uint16_t res;
+} channel[CHANNEL_MAX_NUM + 1];
 
 // ------------------------
 // Public functions
@@ -257,57 +260,56 @@ void MarlinHAL::adc_start(const pin_t pin) {
 
 int8_t pin_to_chan(uint8_t pin) {
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++)
-    if (chan_pin[i] == pin) return i;
+    if (channel[i].pin == pin) return i;
   return -1;
 }
 
 // get PWM channel for pin - if none then attach a new one
 // return -1 if fail or invalid pin#, channel # (0-15) if success
 int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res) {
-  if (pin == 0 || (pin > MAX_PWM_IOPIN)) return -1;     // not a hardware PWM pin!
-  int8_t chan = pin_to_chan(pin);
-  if (chan >= 0) return chan;
+  if (!WITHIN(pin, 1, MAX_PWM_IOPIN)) return -1; // Not a hardware PWM pin!
+  int8_t cid = pin_to_chan(pin);
+  if (cid >= 0) return cid;
 
-  // find an empty adjacent chanel (same timer & freq/res)
+  // Find an empty adjacent channel (same timer & freq/res)
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
-    if (chan_pin[i] == 0) {
-      if (chan_pin[i ^ 0x1] != 0) {
-        if ((chan_freq[i / 2] == freq) && (chan_res[i / 2] == res)) {
-          chan_pin[i] = pin; // allocate pwm to this channel
+    if (channel[i].pin == 0) {
+      if (channel[i ^ 0x1].pin != 0) {
+        if (channel[i / 2].freq == freq && channel[i / 2].res == res) {
+          channel[i].pin = pin; // Allocate PWM to this channel
           ledcAttachPin(pin, i);
           return i;
         }
       }
-      else if (chan == -1) { // pair of empty channels?
-        chan = i & 0xfe; // save lower channel number
-      }
+      else if (cid == -1)    // Pair of empty channels?
+        cid = i & 0xfe;      // Save lower channel number
     }
   }
   // not attached, is an empty timer slot avail?
-  if (chan >= 0) {
-    chan_freq[chan / 2] = freq;
-    chan_pin[chan] = pin;
-    chan_res[chan / 2] = res;
-    ledcSetup(chan, freq, res);
-    ledcAttachPin(pin, chan);
+  if (cid >= 0) {
+    channel[cid / 2].freq = freq;
+    channel[cid].pin = pin;
+    channel[cid / 2].res = res;
+    ledcSetup(cid, freq, res);
+    ledcAttachPin(pin, cid);
   }
-  return chan; // -1 if no channel avail
+  return cid; // -1 if no channel avail
 }
 
 void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=_BV(PWM_RESOLUTION)-1*/, const bool invert/*=false*/) {
-  int8_t channel = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
-  if (channel >= 0) {
+  const int8_t cid = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
+  if (cid >= 0) {
     uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
-    ledcWrite(channel, duty);
+    ledcWrite(cid, duty);
   }
 }
 
-uint8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
-  int8_t channel = pin_to_chan(pin);
-  if (channel >= 0) {
-    if (f_desired == ledcReadFreq(channel)) return channel; // no freq change
-    ledcDetachPin(chan_pin[channel]);
-    chan_pin[channel] = 0;              // remove old freq channel
+int8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
+  const int8_t cid = pin_to_chan(pin);
+  if (cid >= 0) {
+    if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
+    ledcDetachPin(channel[cid].pin);
+    channel[cid].pin = 0;              // remove old freq channel
   }
   return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
 }
@@ -315,16 +317,16 @@ uint8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired)
 // use hardware PWM if avail, if not then ISR
 void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PWM_FREQUENCY*/, const uint16_t res/*=8*/) { // always 8 bit resolution!
   // Use ledc hardware for internal pins
-  int8_t channel = get_pwm_channel(pin, freq, res);
-  if (channel >= 0) {
-    ledcWrite(channel, value); // set duty value
+  const int8_t cid = get_pwm_channel(pin, freq, res);
+  if (cid >= 0) {
+    ledcWrite(cid, value); // set duty value
   }
   else { // not a hardware PWM pin OR no PWM channels available
     int idx = -1;
 
     // Search Pin
     for (int i = 0; i < numPWMUsed; ++i)
-      if (pwmPins[i] == pin) { idx = i; break; }
+      if (pwmInfo[i].pin == pin) { idx = i; break; }
 
     // not found ?
     if (idx < 0) {
@@ -333,7 +335,7 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
 
       // Take new slot for pin
       idx = numPWMUsed;
-      pwmPins[idx] = pin;
+      pwmInfo[idx].pin = pin;
       // Start timer on first use
       if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
 
@@ -341,7 +343,7 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
     }
 
     // Use 7bit internal value - add 1 to have 100% high at 255
-    pwmValues[idx] = (value + 1) / 2;
+    pwmInfo[idx].value = (value + 1) / 2;
   }
 }
 
@@ -353,9 +355,9 @@ HAL_PWM_TIMER_ISR() {
 
   for (int i = 0; i < numPWMUsed; ++i) {
     if (count == 0)                   // Start of interval
-      WRITE(pwmPins[i], pwmValues[i] ? HIGH : LOW);
-    else if (pwmValues[i] == count)   // End of duration
-      WRITE(pwmPins[i], LOW);
+      digitalWrite(pwmInfo[i].pin, pwmInfo[i].value ? HIGH : LOW);
+    else if (pwmInfo[i].value == count)   // End of duration
+      digitalWrite(pwmInfo[i].pin, LOW);
   }
 
   // 128 for 7 Bit resolution
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index f37dd62a8688..b5d10db8f2e4 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -226,6 +226,6 @@ class MarlinHAL {
    * Allocate and set the frequency of a hardware PWM pin
    * Returns -1 if no pin available.
    */
-  static uint8_t set_pwm_frequency(const pin_t pin, const uint32_t f_desired);
+  static int8_t set_pwm_frequency(const pin_t pin, const uint32_t f_desired);
 
 };
diff --git a/Marlin/src/HAL/ESP32/Servo.cpp b/Marlin/src/HAL/ESP32/Servo.cpp
index de72b7110480..ca3950d07f75 100644
--- a/Marlin/src/HAL/ESP32/Servo.cpp
+++ b/Marlin/src/HAL/ESP32/Servo.cpp
@@ -41,7 +41,7 @@ int8_t Servo::attach(const int inPin) {
 
 // leave channel connected to servo - set duty to zero
 void Servo::detach() {
-  if (channel != -1) ledcWrite(channel, 0);
+  if (channel >= 0) ledcWrite(channel, 0);
 }
 
 int Servo::read() { return degrees; }

From 5f9d625c1c7e4ea6cfb5d09bf1b321a11f92a298 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Sat, 26 Feb 2022 14:59:52 -0600
Subject: [PATCH 08/18] outdent

---
 Marlin/src/HAL/ESP32/HAL.cpp | 37 ++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 76037e372386..33c18471be01 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -320,31 +320,32 @@ void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PW
   const int8_t cid = get_pwm_channel(pin, freq, res);
   if (cid >= 0) {
     ledcWrite(cid, value); // set duty value
+    return;
   }
-  else { // not a hardware PWM pin OR no PWM channels available
-    int idx = -1;
 
-    // Search Pin
-    for (int i = 0; i < numPWMUsed; ++i)
-      if (pwmInfo[i].pin == pin) { idx = i; break; }
+  // not a hardware PWM pin OR no PWM channels available
+  int idx = -1;
 
-    // not found ?
-    if (idx < 0) {
-      // No slots remaining
-      if (numPWMUsed >= MAX_PWM_PINS) return;
+  // Search Pin
+  for (int i = 0; i < numPWMUsed; ++i)
+    if (pwmInfo[i].pin == pin) { idx = i; break; }
 
-      // Take new slot for pin
-      idx = numPWMUsed;
-      pwmInfo[idx].pin = pin;
-      // Start timer on first use
-      if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
+  // not found ?
+  if (idx < 0) {
+    // No slots remaining
+    if (numPWMUsed >= MAX_PWM_PINS) return;
 
-      ++numPWMUsed;
-    }
+    // Take new slot for pin
+    idx = numPWMUsed;
+    pwmInfo[idx].pin = pin;
+    // Start timer on first use
+    if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
 
-    // Use 7bit internal value - add 1 to have 100% high at 255
-    pwmInfo[idx].value = (value + 1) / 2;
+    ++numPWMUsed;
   }
+
+  // Use 7bit internal value - add 1 to have 100% high at 255
+  pwmInfo[idx].value = (value + 1) / 2;
 }
 
 // Handle PWM timer interrupt

From a8bd231ad8559b1830e8780a7773a17c432b4617 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Sat, 26 Feb 2022 14:49:43 -0600
Subject: [PATCH 09/18] use structs, replace WRITE

---
 Marlin/src/HAL/ESP32/HAL.cpp   | 114 +++++++++++++++++----------------
 Marlin/src/HAL/ESP32/HAL.h     |   2 +-
 Marlin/src/HAL/ESP32/Servo.cpp |   2 +-
 3 files changed, 61 insertions(+), 57 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index e2b8f111bfd5..5bc49b6689d0 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -73,12 +73,16 @@ uint16_t MarlinHAL::adc_result;
 esp_adc_cal_characteristics_t characteristics[ADC_ATTEN_MAX];
 adc_atten_t attenuations[ADC1_CHANNEL_MAX] = {};
 uint32_t thresholds[ADC_ATTEN_MAX];
-volatile int numPWMUsed = 0,
-             pwmPins[MAX_PWM_PINS],
-             pwmValues[MAX_PWM_PINS];
+
+volatile int numPWMUsed = 0;
+volatile struct { pin_t pin; int value; } pwmState[MAX_PWM_PINS];
+
 pin_t chan_pin[CHANNEL_MAX_NUM + 1] = { 0 }; // PWM capable IOpins - not 0 or >33 on ESP32
-uint32_t chan_freq[(CHANNEL_MAX_NUM + 1) / 2]; // ledcReadFreq doesn't work if a duty hasn't been set yet!
-uint16_t chan_res[(CHANNEL_MAX_NUM + 1) / 2];
+
+struct {
+  uint32_t freq; // ledcReadFreq doesn't work if a duty hasn't been set yet!
+  uint16_t res;
+} pwmInfo[(CHANNEL_MAX_NUM + 1) / 2];
 
 // ------------------------
 // Public functions
@@ -255,7 +259,7 @@ void MarlinHAL::adc_start(const pin_t pin) {
 // PWM
 // ------------------------
 
-int8_t pin_to_chan(uint8_t pin) {
+int8_t channel_for_pin(const uint8_t pin) {
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++)
     if (chan_pin[i] == pin) return i;
   return -1;
@@ -264,50 +268,49 @@ int8_t pin_to_chan(uint8_t pin) {
 // get PWM channel for pin - if none then attach a new one
 // return -1 if fail or invalid pin#, channel # (0-15) if success
 int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res) {
-  if (pin == 0 || (pin > MAX_PWM_IOPIN)) return -1;     // not a hardware PWM pin!
-  int8_t chan = pin_to_chan(pin);
-  if (chan >= 0) return chan;
+  if (!WITHIN(pin, 1, MAX_PWM_IOPIN)) return -1; // Not a hardware PWM pin!
+  int8_t cid = channel_for_pin(pin);
+  if (cid >= 0) return cid;
 
-  // find an empty adjacent chanel (same timer & freq/res)
+  // Find an empty adjacent channel (same timer & freq/res)
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
     if (chan_pin[i] == 0) {
       if (chan_pin[i ^ 0x1] != 0) {
-        if ((chan_freq[i / 2] == freq) && (chan_res[i / 2] == res)) {
-          chan_pin[i] = pin; // allocate pwm to this channel
+        if (pwmInfo[i / 2].freq == freq && pwmInfo[i / 2].res == res) {
+          chan_pin[i] = pin; // Allocate PWM to this channel
           ledcAttachPin(pin, i);
           return i;
         }
       }
-      else if (chan == -1) { // pair of empty channels?
-        chan = i & 0xfe; // save lower channel number
-      }
+      else if (cid == -1)    // Pair of empty channels?
+        cid = i & 0xFE;      // Save lower channel number
     }
   }
   // not attached, is an empty timer slot avail?
-  if (chan >= 0) {
-    chan_freq[chan / 2] = freq;
-    chan_pin[chan] = pin;
-    chan_res[chan / 2] = res;
-    ledcSetup(chan, freq, res);
-    ledcAttachPin(pin, chan);
+  if (cid >= 0) {
+    chan_pin[cid] = pin;
+    pwmInfo[cid / 2].freq = freq;
+    pwmInfo[cid / 2].res = res;
+    ledcSetup(cid, freq, res);
+    ledcAttachPin(pin, cid);
   }
-  return chan; // -1 if no channel avail
+  return cid; // -1 if no channel avail
 }
 
 void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=_BV(PWM_RESOLUTION)-1*/, const bool invert/*=false*/) {
-  int8_t channel = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
-  if (channel >= 0) {
+  const int8_t cid = get_pwm_channel(pin, PWM_FREQUENCY, PWM_RESOLUTION);
+  if (cid >= 0) {
     uint32_t duty = map(invert ? v_size - v : v, 0, v_size, 0, _BV(PWM_RESOLUTION)-1);
-    ledcWrite(channel, duty);
+    ledcWrite(cid, duty);
   }
 }
 
-uint8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
-  int8_t channel = pin_to_chan(pin);
-  if (channel >= 0) {
-    if (f_desired == ledcReadFreq(channel)) return channel; // no freq change
-    ledcDetachPin(chan_pin[channel]);
-    chan_pin[channel] = 0;              // remove old freq channel
+int8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
+  const int8_t cid = channel_for_pin(pin);
+  if (cid >= 0) {
+    if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
+    ledcDetachPin(chan_pin[cid]);
+    chan_pin[cid] = 0;              // remove old freq channel
   }
   return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
 }
@@ -315,34 +318,35 @@ uint8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired)
 // use hardware PWM if avail, if not then ISR
 void analogWrite(const pin_t pin, const uint16_t value, const uint32_t freq/*=PWM_FREQUENCY*/, const uint16_t res/*=8*/) { // always 8 bit resolution!
   // Use ledc hardware for internal pins
-  int8_t channel = get_pwm_channel(pin, freq, res);
-  if (channel >= 0) {
-    ledcWrite(channel, value); // set duty value
+  const int8_t cid = get_pwm_channel(pin, freq, res);
+  if (cid >= 0) {
+    ledcWrite(cid, value); // set duty value
+    return;
   }
-  else { // not a hardware PWM pin OR no PWM channels available
-    int idx = -1;
 
-    // Search Pin
-    for (int i = 0; i < numPWMUsed; ++i)
-      if (pwmPins[i] == pin) { idx = i; break; }
+  // not a hardware PWM pin OR no PWM channels available
+  int idx = -1;
 
-    // not found ?
-    if (idx < 0) {
-      // No slots remaining
-      if (numPWMUsed >= MAX_PWM_PINS) return;
+  // Search Pin
+  for (int i = 0; i < numPWMUsed; ++i)
+    if (pwmState[i].pin == pin) { idx = i; break; }
 
-      // Take new slot for pin
-      idx = numPWMUsed;
-      pwmPins[idx] = pin;
-      // Start timer on first use
-      if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
+  // not found ?
+  if (idx < 0) {
+    // No slots remaining
+    if (numPWMUsed >= MAX_PWM_PINS) return;
 
-      ++numPWMUsed;
-    }
+    // Take new slot for pin
+    idx = numPWMUsed;
+    pwmState[idx].pin = pin;
+    // Start timer on first use
+    if (idx == 0) HAL_timer_start(MF_TIMER_PWM, PWM_TIMER_FREQUENCY);
 
-    // Use 7bit internal value - add 1 to have 100% high at 255
-    pwmValues[idx] = (value + 1) / 2;
+    ++numPWMUsed;
   }
+
+  // Use 7bit internal value - add 1 to have 100% high at 255
+  pwmState[idx].value = (value + 1) / 2;
 }
 
 // Handle PWM timer interrupt
@@ -353,9 +357,9 @@ HAL_PWM_TIMER_ISR() {
 
   for (int i = 0; i < numPWMUsed; ++i) {
     if (count == 0)                   // Start of interval
-      WRITE(pwmPins[i], pwmValues[i] ? HIGH : LOW);
-    else if (pwmValues[i] == count)   // End of duration
-      WRITE(pwmPins[i], LOW);
+      digitalWrite(pwmState[i].pin, pwmState[i].value ? HIGH : LOW);
+    else if (pwmState[i].value == count)   // End of duration
+      digitalWrite(pwmState[i].pin, LOW);
   }
 
   // 128 for 7 Bit resolution
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index f37dd62a8688..b5d10db8f2e4 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -226,6 +226,6 @@ class MarlinHAL {
    * Allocate and set the frequency of a hardware PWM pin
    * Returns -1 if no pin available.
    */
-  static uint8_t set_pwm_frequency(const pin_t pin, const uint32_t f_desired);
+  static int8_t set_pwm_frequency(const pin_t pin, const uint32_t f_desired);
 
 };
diff --git a/Marlin/src/HAL/ESP32/Servo.cpp b/Marlin/src/HAL/ESP32/Servo.cpp
index de72b7110480..ca3950d07f75 100644
--- a/Marlin/src/HAL/ESP32/Servo.cpp
+++ b/Marlin/src/HAL/ESP32/Servo.cpp
@@ -41,7 +41,7 @@ int8_t Servo::attach(const int inPin) {
 
 // leave channel connected to servo - set duty to zero
 void Servo::detach() {
-  if (channel != -1) ledcWrite(channel, 0);
+  if (channel >= 0) ledcWrite(channel, 0);
 }
 
 int Servo::read() { return degrees; }

From 4ef39893a92c3bac3ed29e7f8b21aab274e8b836 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 28 Feb 2022 10:29:13 +0000
Subject: [PATCH 10/18] Array changes

Initialise pin array to zeroes.  Revert to separate pin array to save a few bytes of memory (freq & res arrays only need to be 8 deep).
---
 Marlin/src/HAL/ESP32/HAL.cpp | 28 ++++++++++++++--------------
 Marlin/src/HAL/ESP32/HAL.h   |  2 +-
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 33c18471be01..43763e80856f 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -77,11 +77,11 @@ uint32_t thresholds[ADC_ATTEN_MAX];
 volatile int numPWMUsed = 0;
 volatile struct { pin_t pin; int value; } pwmInfo[MAX_PWM_PINS];
 
+pin_t chanPin[CHANNEL_MAX_NUM + 1] = { 0 };  // PWM capable IOpins - not 0 or >33 on ESP32
 struct {
-  pin_t    pin;  // PWM capable IOpins - not 0 or >33 on ESP32
   uint32_t freq; // ledcReadFreq doesn't work if a duty hasn't been set yet!
   uint16_t res;
-} channel[CHANNEL_MAX_NUM + 1];
+} pwmTimer[(CHANNEL_MAX_NUM + 1) / 2];
 
 // ------------------------
 // Public functions
@@ -258,9 +258,9 @@ void MarlinHAL::adc_start(const pin_t pin) {
 // PWM
 // ------------------------
 
-int8_t pin_to_chan(uint8_t pin) {
+int8_t pin_to_chan(pin_t pin) {
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++)
-    if (channel[i].pin == pin) return i;
+    if (chanPin[i] == pin) return i;
   return -1;
 }
 
@@ -273,10 +273,10 @@ int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res)
 
   // Find an empty adjacent channel (same timer & freq/res)
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++) {
-    if (channel[i].pin == 0) {
-      if (channel[i ^ 0x1].pin != 0) {
-        if (channel[i / 2].freq == freq && channel[i / 2].res == res) {
-          channel[i].pin = pin; // Allocate PWM to this channel
+    if (chanPin[i] == 0) {
+      if (chanPin[i ^ 0x1] != 0) {
+        if (pwmTimer[i / 2].freq == freq && pwmTimer[i / 2].res == res) {
+          chanPin[i] = pin; // Allocate PWM to this channel
           ledcAttachPin(pin, i);
           return i;
         }
@@ -287,9 +287,9 @@ int8_t get_pwm_channel(const pin_t pin, const uint32_t freq, const uint16_t res)
   }
   // not attached, is an empty timer slot avail?
   if (cid >= 0) {
-    channel[cid / 2].freq = freq;
-    channel[cid].pin = pin;
-    channel[cid / 2].res = res;
+    pwmTimer[cid / 2].freq = freq;
+    pwmTimer[cid / 2].res = res;
+    chanPin[cid] = pin;
     ledcSetup(cid, freq, res);
     ledcAttachPin(pin, cid);
   }
@@ -307,9 +307,9 @@ void MarlinHAL::set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v
 int8_t MarlinHAL::set_pwm_frequency(const pin_t pin, const uint32_t f_desired) {
   const int8_t cid = pin_to_chan(pin);
   if (cid >= 0) {
-    if (f_desired == ledcReadFreq(cid)) return cid; // no freq change
-    ledcDetachPin(channel[cid].pin);
-    channel[cid].pin = 0;              // remove old freq channel
+    if (f_desired == pwmTimer[cid / 2].freq) return cid; // no freq change
+    ledcDetachPin(chanPin[cid]);
+    chanPin[cid] = 0;              // remove old freq channel
   }
   return get_pwm_channel(pin, f_desired, PWM_RESOLUTION); // try for new one
 }
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index b5d10db8f2e4..8b26c3471d39 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -67,7 +67,7 @@
 #define HAL_CAN_SET_PWM_FREQ   // This HAL supports PWM Frequency adjustment
 #define PWM_FREQUENCY  1000u   // Default PWM frequency when set_pwm_duty() is called without set_pwm_frequency()
 #define PWM_RESOLUTION   10u   // Default PWM bit resolution
-#define CHANNEL_MAX_NUM  15u   // max PWM channel to allocate (7 to only use low speed, 15 to use high speed - see above)
+#define CHANNEL_MAX_NUM  15u   // max PWM channel # to allocate (7 to only use low speed, 15 to use low & high)
 #define MAX_PWM_IOPIN    33u   // hardware pwm pins < 34
 
 // ------------------------

From 381c2bc145847f3afa38fb1a0f7b45e060897bf9 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 28 Feb 2022 10:59:27 +0000
Subject: [PATCH 11/18] fixed chanPin variable name

---
 Marlin/src/HAL/ESP32/HAL.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 60dbafb4f9cc..69cf1c3fe209 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -263,7 +263,7 @@ void MarlinHAL::adc_start(const pin_t pin) {
 
 int8_t channel_for_pin(const uint8_t pin) {
   for (int i = 0; i <= CHANNEL_MAX_NUM; i++)
-    if (chanPin[i] == pin) return i;
+    if (chan_pin[i] == pin) return i;
   return -1;
 }
 

From 76a4b3ffb71bcec10cda0b14676a1738745d463c Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Sun, 13 Mar 2022 10:45:14 +0000
Subject: [PATCH 12/18] Update Configuration_adv.h

Comment update.
---
 Marlin/Configuration_adv.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index 83a8eaa0fb87..8ee24063e0e4 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -3465,7 +3465,7 @@
   #define SPINDLE_LASER_USE_PWM                // Enable if your controller supports setting the speed/power
   #if ENABLED(SPINDLE_LASER_USE_PWM)
     #define SPINDLE_LASER_PWM_INVERT    false  // Set to "true" if the speed/power goes up when you want it to go slower
-    #define SPINDLE_LASER_FREQUENCY     2500   // (Hz) Spindle/laser frequency (only on supported HALs: AVR and LPC)
+    #define SPINDLE_LASER_FREQUENCY     2500   // (Hz) Spindle/laser frequency (only on supported HALs: AVR, ESP32 and LPC)
   #endif
 
   //#define AIR_EVACUATION                     // Cutter Vacuum / Laser Blower motor control with G-codes M10-M11

From 407d9f54c3e0d2246e84291f8c73b871a88c1126 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 14 Mar 2022 17:20:58 +0000
Subject: [PATCH 13/18] Change ADC ref for MKS TinyBee

MKS TinyBee uses a 2.5V ADC reference instead of a 3.3V on other ESP32 boards.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 69cf1c3fe209..aceae7a73e0e 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -240,7 +240,7 @@ void MarlinHAL::adc_start(const pin_t pin) {
   const adc1_channel_t chan = get_channel(pin);
   uint32_t mv;
   esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);
-  adc_result = mv * 1023.0 / 3300.0;
+  adc_result = mv * 1023.0 / TERN(MB(MKS_TINYBEE), 2500.0, 3300.0); // TinyBee uses 2.5v VDDA ref
 
   // Change the attenuation level based on the new reading
   adc_atten_t atten;

From 8259ee9884645f9de550ee20da9bc99ad4de1b9b Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 14 Mar 2022 17:32:27 +0000
Subject: [PATCH 14/18] Corrects ADC Vref divisor for MKS TinyBee

MKS TinyBee uses a 2.5V VDDA ADC reference instead of the more common 3.3V.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index aceae7a73e0e..785fce7d6f67 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -240,8 +240,12 @@ void MarlinHAL::adc_start(const pin_t pin) {
   const adc1_channel_t chan = get_channel(pin);
   uint32_t mv;
   esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);
-  adc_result = mv * 1023.0 / TERN(MB(MKS_TINYBEE), 2500.0, 3300.0); // TinyBee uses 2.5v VDDA ref
-
+  #if MB(MKS_TINYBEE)
+  adc_result = mv * 1023.0 / 2500.0; // TinyBee uses 2.5v VDDA ref
+  #else
+  adc_result = mv * 1023.0 / 3300.0;
+  #endif
+  
   // Change the attenuation level based on the new reading
   adc_atten_t atten;
   if (mv < thresholds[ADC_ATTEN_DB_0] - 100)

From 8bccc11d474c1cd099ba8b870bb7018b1a5b3f01 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 14 Mar 2022 17:49:01 +0000
Subject: [PATCH 15/18] Revert "Corrects ADC Vref divisor for MKS TinyBee"

This reverts commit 8259ee9884645f9de550ee20da9bc99ad4de1b9b.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 785fce7d6f67..aceae7a73e0e 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -240,12 +240,8 @@ void MarlinHAL::adc_start(const pin_t pin) {
   const adc1_channel_t chan = get_channel(pin);
   uint32_t mv;
   esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);
-  #if MB(MKS_TINYBEE)
-  adc_result = mv * 1023.0 / 2500.0; // TinyBee uses 2.5v VDDA ref
-  #else
-  adc_result = mv * 1023.0 / 3300.0;
-  #endif
-  
+  adc_result = mv * 1023.0 / TERN(MB(MKS_TINYBEE), 2500.0, 3300.0); // TinyBee uses 2.5v VDDA ref
+
   // Change the attenuation level based on the new reading
   adc_atten_t atten;
   if (mv < thresholds[ADC_ATTEN_DB_0] - 100)

From 63c296592870491d65a0ac84c4fa7ef1730e3095 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 14 Mar 2022 17:49:06 +0000
Subject: [PATCH 16/18] Revert "Change ADC ref for MKS TinyBee"

This reverts commit 407d9f54c3e0d2246e84291f8c73b871a88c1126.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index aceae7a73e0e..69cf1c3fe209 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -240,7 +240,7 @@ void MarlinHAL::adc_start(const pin_t pin) {
   const adc1_channel_t chan = get_channel(pin);
   uint32_t mv;
   esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);
-  adc_result = mv * 1023.0 / TERN(MB(MKS_TINYBEE), 2500.0, 3300.0); // TinyBee uses 2.5v VDDA ref
+  adc_result = mv * 1023.0 / 3300.0;
 
   // Change the attenuation level based on the new reading
   adc_atten_t atten;

From 931fd6bc453128326687e4d75e883e951ef7a8fb Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 14 Mar 2022 17:51:06 +0000
Subject: [PATCH 17/18] Correct ADC Vref divisor for MKS TinyBee

MKS TinyBee uses a 2.5V VDDA ADC reference instead of the more common 3.3V.  2500.0 = 2.5V.
Board uses a Zener diode - measuring the actual voltage on any disconnected thermistor pin and using that value ( x 1000) will improve precision.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 69cf1c3fe209..2836120da045 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -240,8 +240,12 @@ void MarlinHAL::adc_start(const pin_t pin) {
   const adc1_channel_t chan = get_channel(pin);
   uint32_t mv;
   esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);
-  adc_result = mv * 1023.0 / 3300.0;
-
+  #if MB(MKS_TINYBEE)
+    adc_result = mv * 1023.0 / 2500.0; // TinyBee uses 2.5v VDDA ref
+  #else
+    adc_result = mv * 1023.0 / 3300.0;
+  #endif
+  
   // Change the attenuation level based on the new reading
   adc_atten_t atten;
   if (mv < thresholds[ADC_ATTEN_DB_0] - 100)

From 47e60673f3f0cc242abf07e9c9daf1a8b84576c5 Mon Sep 17 00:00:00 2001
From: JohnR <john@cirtech.co.uk>
Date: Mon, 14 Mar 2022 17:58:18 +0000
Subject: [PATCH 18/18] Revert "Correct ADC Vref divisor for MKS TinyBee"

This reverts commit 931fd6bc453128326687e4d75e883e951ef7a8fb.
---
 Marlin/src/HAL/ESP32/HAL.cpp | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/Marlin/src/HAL/ESP32/HAL.cpp b/Marlin/src/HAL/ESP32/HAL.cpp
index 2836120da045..69cf1c3fe209 100644
--- a/Marlin/src/HAL/ESP32/HAL.cpp
+++ b/Marlin/src/HAL/ESP32/HAL.cpp
@@ -240,12 +240,8 @@ void MarlinHAL::adc_start(const pin_t pin) {
   const adc1_channel_t chan = get_channel(pin);
   uint32_t mv;
   esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);
-  #if MB(MKS_TINYBEE)
-    adc_result = mv * 1023.0 / 2500.0; // TinyBee uses 2.5v VDDA ref
-  #else
-    adc_result = mv * 1023.0 / 3300.0;
-  #endif
-  
+  adc_result = mv * 1023.0 / 3300.0;
+
   // Change the attenuation level based on the new reading
   adc_atten_t atten;
   if (mv < thresholds[ADC_ATTEN_DB_0] - 100)