內接 LED：高電位驅動

The ESP32 chip comes with 48 pins with multiple functions. Not all pins are exposed in all ESP32 development boards, and some pins cannot be used.

ESP32 peripherals include:

• 18 Analog-to-Digital Converter (ADC) channels

• 3 SPI interfaces

• 3 UART interfaces

• 2 I2C interfaces

• 16 PWM output channels

• 2 Digital-to-Analog Converters (DAC)

• 2 I2S interfaces

• 10 Capacitive sensing GPIOs

• GPIO6, GPIO7, GPIO8, GPIO9, GPIO10, and GPIO11 pins, you must not use them because they are connected to the flash memory of the ESP32: if you use them, the ESP32 will not work. 

• The GPIO1 (TX0) and GPIO3 (RX0) pins are used to communicate with the computer in UART via USB. If you use them, you will not be able to upload programs to the board or use the serial monitor via the USB port.

• Pins GPIO36 (VP), GPIO39 (VN), GPIO34, and GPIO35 can only be used as input. They also do not have internal pull-up and pull-down resistors (pinMode(36, INPUT_PULLUP) or pinMode(36, INPUT_PULLDOWN) cannot be used).

• ESP32 Strapping Pins: pins have a unique function when starting the ESP32. GPIO0, GPIO2, GPIO12 (MTDI) and GPIO15 (MTDO) . You can use them, but you must be careful when setting a logic state (3.3V or 0V) with an external pull-up or pull-down resistor.

• When booting the ESP32, during a short period, some pins quickly change their logic states (0V → 3.3V). You may have weird bugs with these pins: for example, a relay that temporarily activates. The faulty pins are the following:

  • GPIO 1 : Sends the ESP32 boot logs via the UART

  • GPIO 3 : 3.3V voltage at boot time

  • GPIO 5 : Sends a PWM signal at boot time

  • GPIO 14 : Sends a PWM signal at boot time

  • GPIO 15 : Sends the ESP32 boot logs via the UART

• The EN pin can activate or deactivate the ESP32 via an external wire. It is connected to the board’s EN button. When the ESP32 is on, it is at 3.3V. If you put this pin to the ground, the ESP32 is off. This can be used when the ESP32 is in a box and you want to be able to turn it on/off with a switch.

• On boards that use an ESP32-WROVER module to have more RAM, then the GPIO16 and GPIO17 pins are not available because they are used internally by the PSRAM.

參考

• ESP32 Wroom Devkit Pinout: Use the ESP32 GPIO pins

•