🐛 MKS TinyBee - 2.5V ADC Vref (#23903)

Marlin/src/HAL/ESP32/HAL.cpp

   }
 }
 
+#ifndef ADC_REFERENCE_VOLTAGE
+  #define ADC_REFERENCE_VOLTAGE 3.3
+#endif
+
 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 * 1023.0f / float(ADC_REFERENCE_VOLTAGE) / 1000.0f;
 
   // Change the attenuation level based on the new reading
   adc_atten_t atten;

Marlin/src/pins/esp32/pins_MKS_TINYBEE.h

 //#define E1_AUTO_FAN_PIN                    149  // need to update Configuration_adv.h @section extruder
 
 //
+// ADC Reference Voltage
+//
+#define ADC_REFERENCE_VOLTAGE                2.5  // 2.5V reference VDDA
+
+//
 // MicroSD card
 //
 #define SD_MOSI_PIN                           23