ESP32-PICO datasheet(23/64 Pages) ESPRESSIF

23 / 64 page

3 Boot Configurations

Boot Configurations

Note:

The content below is excerpted from ESP32 Series Datasheet > Section Boot Configurations.

The chip allows for configuring the following boot parameters through strapping pins and eFuse bits at

power-up or a hardware reset, without microcontroller interaction.

• Chip boot mode

– Strapping pin: GPIO0 and GPIO2

• Internal LDO (VDD_SDIO) Voltage

– Strapping pin: MTDI

– eFuse bit: EFUSE_SDIO_FORCE and EFUSE_SDIO_TIEH

• U0TXD printing

– Strapping pin: MTDO

• Timing of SDIO Slave

– Strapping pin: MTDO and GPIO5

• JTAG signal source

– eFuse bit: EFUSE_DISABLE_JTAG

The default values of all the above eFuse bits are 0, which means that they are not burnt. Given that eFuse is

one-time programmable, once an eFuse bit is programmed to 1, it can never be reverted to 0. For how to

program eFuse bits, please refer to ESP32 Technical Reference Manual > Chapter eFuse Controller.

The default values of the strapping pins, namely the logic levels, are determined by pins’ internal weak

pull-up/pull-down resistors at reset if the pins are not connected to any circuit, or connected to an external

high-impedance circuit.

Table 8: Default Configuration of Strapping Pins

Strapping Pin

Default Configuration

Bit Value

GPIO0

Pull-up

GPIO2

Pull-down

MTDI

Pull-down

MTDO

Pull-up

GPIO5

Pull-up

To change the bit values, the strapping pins should be connected to external pull-down/pull-up resistances. If

the ESP32 is used as a device by a host MCU, the strapping pin voltage levels can also be controlled by the

host MCU.

All strapping pins have latches. At system reset, the latches sample the bit values of their respective strapping

pins and store them until the chip is powered down or shut down. The states of latches cannot be changed in

Espressif Systems

Submit Documentation Feedback

ESP32-PICO Series Datasheet v1.1

ESP32-PICO Folha de dados(PDF) 23 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.

ESP32-PICO Folha de dados(HTML) 23 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

Folha de dados Download

Ligação URL