ESP32C3 datasheet(14/44 Pages) ESPRESSIF

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Pin Definition

To change the strapping bit values, you can apply the external pull-down/pull-up resistances, or use the host

MCU’s GPIOs to control the voltage level of these pins when powering on ESP32-C3.

After reset, the strapping pins work as normal-function pins.

Table 4 lists detailed booting configurations of the strapping pins.

Table 4: Strapping Pins

Booting Mode 1

Default

SPI Boot

Download Boot

GPIO2

N/A

GPIO8

N/A

Don’t care

GPIO9

Internal weak

pull-up

Enabling/Disabling ROM Messages Print During Booting

Default

Functionality

GPIO8

N/A

When the value of eFuse field EFUSE_UART_PRINT_CONTROL is

0 (default), print is enabled and not controlled by GPIO8.

1, if GPIO8 is 0, print is enabled; if GPIO8 is 1, it is disabled.

2, if GPIO8 is 0, print is disabled; if GPIO8 is 1, it is enabled.

3, print is disabled and not controlled by GPIO8.

1 The strapping combination of GPIO8 = 0 and GPIO9 = 0 is invalid and will trigger unexpected be-

havior.

Figure 6 shows the setup and hold times for the strapping pins before and after the CHIP_EN signal goes high.

Details about the parameters are listed in Table 5.

CHIP_EN

Strapping pin

IL_nRST

Figure 6: Setup and Hold Times for the Strapping Pins

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ESP32-C3 Series Datasheet v1.1

ESP32C3 Datasheet(PDF) 14 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.