User's Manual

PRELIMINARY
2. Pin Definitions
Note:
• Firmware can configure register bits to change the settings of ”Voltage of Internal LDO (VDD_SDIO)” and
”Timing of SDIO Slave” after booting.
• Internal pull-up resistor (R9) for MTDI is not populated in the module, as the flash and SRAM in ESP32-
WROOM-32E only support a power voltage of 3.3 V (output by VDD_SDIO)
Espressif Systems 6 ESP32-WROOM-32E User Manual
Booting Mode
Pin
Default
SPI Boot
Download Boot
GPIO0
Pull-up
1
0
GPIO2
Pull-down
Don’t-care
0
Enabling/Disabling Debugging Log Print over U0TXD During Booting
Pin
Default
U0TXD Active
U0TXD Silent
MTDO
Pull-up
1
0
Timing of SDIO Slave
Pin
Default
Falling-edge Sampling
Falling-edge Output
Falling-edge Sampling
Rising-edge Output
Rising-edge Sampling
Falling-edge Output
Rising-edge Sampling
Rising-edge Output
MTDO
Pull-up
0
0
1
1
GPIO5
Pull-up
0
1
0
1