Gpio & Rtc Gpio - Espressif ESP32-S2 Programming Manual

Chapter 2. API Reference
TIMER_SRC_CLK_APB = 0
Select APB as the source clock
TIMER_SRC_CLK_XTAL = 1
Select XTAL as the source clock
2.2.4 GPIO & RTC GPIO
Overview
The ESP32-S2 chip features 43 physical GPIO pads. Some GPIO pads cannot be used or do not have the corre-
sponding pin on the chip package. For more details, see ESP32-S2 Technical Reference Manual > IO MUX and GPIO
Matrix (GPIO, IO_MUX) [PDF]. Each pad can be used as a general purpose I/O or can be connected to an internal
peripheral signal.
The table below provides more information on pin usage, and please note the comments in the table for GPIOs with
restrictions.
GPIO Analog Function
GPIO0
GPIO1 ADC1_CH0
GPIO2 ADC1_CH1
GPIO3 ADC1_CH2
GPIO4 ADC1_CH3
GPIO5 ADC1_CH4
GPIO6 ADC1_CH5
GPIO7 ADC1_CH6
GPIO8 ADC1_CH7
GPIO9 ADC1_CH8
GPIO10 ADC1_CH9
GPIO11 ADC2_CH0
GPIO12 ADC2_CH1
GPIO13 ADC2_CH2
GPIO14 ADC2_CH3
GPIO15 ADC2_CH4
GPIO16 ADC2_CH5
GPIO17 ADC2_CH6
GPIO18 ADC2_CH7
GPIO19 ADC2_CH8
GPIO20 ADC2_CH9
GPIO21
GPIO26
GPIO27
GPIO28
GPIO29
GPIO30
GPIO31
GPIO32
GPIO33
GPIO34
GPIO35
GPIO36
GPIO37
GPIO38
GPIO39
GPIO40
Espressif Systems
RTC GPIO
RTC_GPIO0
RTC_GPIO1
RTC_GPIO2
RTC_GPIO3
RTC_GPIO4
RTC_GPIO5
RTC_GPIO6
RTC_GPIO7
RTC_GPIO8
RTC_GPIO9
RTC_GPIO10
RTC_GPIO11
RTC_GPIO12
RTC_GPIO13
RTC_GPIO14
RTC_GPIO15
RTC_GPIO16
RTC_GPIO17
RTC_GPIO18
RTC_GPIO19
RTC_GPIO20
RTC_GPIO21
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Strapping pin
SPI0/1
SPI0/1
SPI0/1
SPI0/1
SPI0/1
SPI0/1
SPI0/1
JTAG
JTAG
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Release v4.4