🐛 Fix TFT backlight [STM32] (#23062)

Marlin/src/HAL/STM32/fast_pwm.cpp

@@ -28,11 +28,13 @@
 #include "timers.h"
 
 void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=255*/, const bool invert/*=false*/) {
+  if (!PWM_PIN(pin)) return;            // Don't proceed if no hardware timer
+
   PinName pin_name = digitalPinToPinName(pin);
   TIM_TypeDef *Instance = (TIM_TypeDef *)pinmap_peripheral(pin_name, PinMap_PWM);
+
   uint16_t adj_val = Instance->ARR * v / v_size;
   if (invert) adj_val = Instance->ARR - adj_val;
-
   switch (get_pwm_channel(pin_name)) {
     case TIM_CHANNEL_1: LL_TIM_OC_SetCompareCH1(Instance, adj_val); break;
     case TIM_CHANNEL_2: LL_TIM_OC_SetCompareCH2(Instance, adj_val); break;

Marlin/src/HAL/STM32F1/fast_pwm.cpp

@@ -28,6 +28,7 @@
 #include "timers.h"
 
 void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size/*=255*/, const bool invert/*=false*/) {
+  if (!PWM_PIN(pin)) return;
   timer_dev *timer = PIN_MAP[pin].timer_device;
   uint16_t max_val = timer->regs.bas->ARR * v / v_size;
   if (invert) max_val = v_size - max_val;

Marlin/src/lcd/dogm/marlinui_DOGM.cpp

@@ -339,12 +339,14 @@ void MarlinUI::draw_kill_screen() {
 void MarlinUI::clear_lcd() { } // Automatically cleared by Picture Loop
 
 #if HAS_LCD_BRIGHTNESS
+
   void MarlinUI::_set_brightness() {
     #if PIN_EXISTS(TFT_BACKLIGHT)
       if (PWM_PIN(TFT_BACKLIGHT_PIN))
-        set_pwm_duty(pin_t(TFT_BACKLIGHT_PIN), brightness);
+        analogWrite(pin_t(TFT_BACKLIGHT_PIN), backlight ? brightness : 0);
     #endif
   }
+
 #endif
 
 #if HAS_LCD_MENU

Marlin/src/lcd/tft/ui_common.cpp

@@ -210,12 +210,14 @@ void MarlinUI::clear_lcd() {
 }
 
 #if HAS_LCD_BRIGHTNESS
+
   void MarlinUI::_set_brightness() {
     #if PIN_EXISTS(TFT_BACKLIGHT)
       if (PWM_PIN(TFT_BACKLIGHT_PIN))
-        set_pwm_duty(pin_t(TFT_BACKLIGHT_PIN), brightness);
+        analogWrite(pin_t(TFT_BACKLIGHT_PIN), backlight ? brightness : 0);
     #endif
   }
+
 #endif
 
 #if ENABLED(TOUCH_SCREEN_CALIBRATION)

Marlin/src/lcd/tft_io/tft_io.cpp

@@ -152,8 +152,7 @@ if (lcd_id != 0xFFFFFFFF) return;
   #endif
 
   #if PIN_EXISTS(TFT_BACKLIGHT) && ENABLED(DELAYED_BACKLIGHT_INIT)
-    WRITE(TFT_BACKLIGHT_PIN, HIGH);
+    TERN(HAS_LCD_BRIGHTNESS, ui._set_brightness(), WRITE(TFT_BACKLIGHT_PIN, HIGH));
-    TERN_(HAS_LCD_BRIGHTNESS, ui._set_brightness());
   #endif
 }
 

Marlin/src/pins/stm32f1/pins_LONGER3D_LK.h

@@ -89,9 +89,17 @@
 #define HEATER_BED_PIN                      PA8   // pin 67 (Hot Bed Mosfet)
 
 #define FAN_PIN                             PA15  // pin 77 (4cm Fan)
-#define FAN_SOFT_PWM                              // Required to avoid issues with heating or STLink
+#ifdef MAPLE_STM32F1
-#define FAN_MIN_PWM                           35  // Fan will not start in 1-30 range
+  #define FAN_SOFT_PWM                            // Required to avoid issues with heating or STLink
-#define FAN_MAX_PWM                          255
+  #define FAN_MIN_PWM                         35  // Fan will not start in 1-30 range
+  #define FAN_MAX_PWM                        255
+#else
+  #define FAST_PWM_FAN                            // STM32 Variant allow TIMER2 Hardware PWM
+  #define FAST_PWM_FAN_FREQUENCY           31400  // This frequency allow a good range, fan starts at 3%, half noise at 50%
+  #define NEEDS_HARDWARE_PWM                   1
+  #define FAN_MIN_PWM                          5
+  #define FAN_MAX_PWM                        255
+#endif
 
 //#define BEEPER_PIN                        PD13  // pin 60 (Servo PWM output 5V/GND on Board V0G+) made for BL-Touch sensor
                                                   // Can drive a PC Buzzer, if connected between PWM and 5V pins