Espressif Systems ESP32-C3 Series Hardware Design Manuallines page 15

2 Schematic Checklist
Name
XTAL_32K_P
XTAL_32K_N
GPIO2
GPIO3
MTMS
MTDI
MTCK
MTDO
GPIO8
GPIO9
GPIO10
VDD_SPI
SPIHD
SPIWP
SPICS0
SPICLK
SPID
SPIQ
GPIO18
GPIO19
U0RXD
U0TXD
Reset
The default configuration of each pin after reset:
• 0 - input disabled, in high impedance state (IE = 0)
• 1 - input enabled, in high impedance state (IE = 1)
• 2 - input enabled, pull-down resistor enabled (IE = 1, WPD = 1)
• 3 - input enabled, pull-up resistor enabled (IE = 1, WPU = 1)
• 0* - input disabled, pull-up resistor enabled (IE = 0, WPU = 0, USB_WPU = 1). See details in Notes
• 1* - When the value of eFuse bit EFUSE_DIS_PAD_JTAG is
0 (default), input enabled, pull-up resistor enabled (IE = 1, WPU = 1)
1, input enabled, in high impedance state (IE = 1)
We recommend pulling high or low GPIO pins in high impedance state to avoid unnecessary power
consumption. You may add pull-up and pull-down resistors in your PCB design referring to Table DC
Characteristics (3.3 V, 25 °C) in
during software initialization.
Notes
Espressif Systems
Table 4: IO MUX Pin Functions
No. Function 0
4 GPIO0
5 GPIO1
6 GPIO2
8 GPIO3
9 MTMS
10 MTDI
12 MTCK
13 MTDO
14 GPIO8
15 GPIO9
16 GPIO10
18 GPIO11
19 SPIHD
20 SPIWP
21 SPICS0
22 SPICLK
23 SPID
24 SPIQ
25 GPIO18
26 GPIO19
27 U0RXD
28 U0TXD
ESP32-C3 Family Datasheet, or enable internal pull-up and pull-down resistors
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Function 1 Function 2
GPIO0 —
GPIO1 —
GPIO2 FSPIQ
GPIO3 —
GPIO4 FSPIHD
GPIO5 FSPIWP
GPIO6 FSPICLK
GPIO7 FSPID
GPIO8 —
GPIO9 —
GPIO10 FSPICS0
GPIO11 —
GPIO12 —
GPIO13 —
GPIO14 —
GPIO15 —
GPIO16 —
GPIO17 —
GPIO18 —
GPIO19 —
GPIO20 —
GPIO21 —
14
ESP32-C3 Family Hardware Design Guidelines V0.5
Reset Notes
0 R
0 R
1 R
1 R
1 R
1 R
1* G
1 G
1 —
3 —
1 G
0 —
3 —
3 —
3 —
3 —
3 —
3 —
0 USB, G
0* USB
1 G
1 —