Notes for GPIO

Strapping Pin

There are four Strapping pins for ESP32-S3：GPIO0、GPIO45、GPIO46、GPIO3。 With the release of the chip’s system reset (power-on reset, RTC watchdog reset, undervoltage reset), the strapping pins sample the level and store it in the latch as “0” or “1” “, and keep it until the chip is powered off or turned off. Each Strapping pin is connecting to internal pull-up/pull-down. Connecting to high-impedance external circuit or without an external connection, a strapping pin’s default value of input level will be determined by internal weak pull-up/pull-down. To change the value of the Strapping, users can apply an external pulldown/pull-up resistor, or use the GPIO of the host MCU to control the level of the strapping pin when the ESP32-S3’s power on reset is released.

When releasing the reset, the strapping pin has the same function as a normal pin. The followings are default configurations of these four strapping pins at power-on and their functions under the corresponding configuration.

../_images/GPIO_1.png

Note

1.The strapping combination of setting GPIO46 to 1 and GPIO0 to 0 is invalid and may trigger unexpected behavior. 2.By default, the ROM boot messages are printed over UART0 (UOTXD pin) and the USB Serial/JTAG controller together. The ROM code printing can be disabled through the configuration register and eFuse. For detailed information, please refer to the ‘Chip Boot Control’ chapter in the ESP32-S3 Technical Reference Manual.

If you have any difficulties or questions with this tutorial or toolkit, feel free to ask for our quick and free technical support through tech_edu_service@outlook.com at any time. or check: https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom1u_datasheet_en.pdf

PSRAM Pin

The module on the ESP32-S3-WROOM board uses the ESP32-S3R8 chip with 8MB of external Flash. When we use the OPI PSRAM, please note that the GPIO35-GPIO37 on the ESP32-S3-WROOM board will not be available for other purposes. When OPI PSRAM is not used, GPIO35-GPIO37 on the board can be used as normal GPIO.

../_images/GPIO_2.png

SDcard Pin An SDcard slot is integrated on the back of the ESP32-S3-WROOM board. We can use GPIO38-GPIO40 of ESP32-S3-WROOM to drive SD card. The SDcard of ESP32-S3-WROOM uses SDMMC, a 1-bit bus driving method, which has been integrated in the Arduino IDE, and we can call the “SD_MMC.h” library to drive it. For details, see the SDcard chapter in this tutorial.

USB Pin In Micropython, GPIO19 and GPIO20 are used for the USB function of ESP32S3, so they cannot be used as other functions!

Cam Pin When using the camera of our ESP32-S3 WROOM, please check the pins of it. Pins with underlined numbers are used by the camera function, if you want to use other functions besides it, please avoid using them.

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CAM_Pin

GPIO_pin

SIOD

GPIO4

SIOC

GPIO5

CSI_VYSNC

GPIO6

CSI_HREF

GPIO7

CSI_Y9

GPIO16

XCLK

GPIO15

CSI_Y8

GPIO17

CSI_Y7

GPIO18

CSI_PCLK

GPIO13

CSI_Y6

GPIO12

CSI_Y2

GPIO11

CSI_Y5

GPIO10

CSI_Y3

GPIO9

CSI_Y4

GPIO8

If you have any questions about the information of GPIO, you can click here to go back to ESP32-S3 WROOM to view specific information about GPIO. or check: https://www.espressif.com/sites/default/files/documentation/esp32-s3_datasheet_en.pdf