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The ESP32-S from Ai-Thinker is a small-size, low-power wireless module for a wide variety of applications like a low-power sensor with a demanding task such as voice encoding. It is based on the famous ESP32 from Espressif, more precisely the ESP32-D0WDQ6 chip, designed to be scalable and adaptive. Please have a look at the following post for an in-detail description of the related features and specifications of the ESP32 chip (coming soon). The ESP32-S is Ai-Thinker’s equivalent to the ESP32-WROOM-32 module from Espressif, equaling in the form factor and specifications.

ESP32-S Front-View
Front View (Source)
ESP32-S Back View
Back View (Source)

Pin Definitions

ESP32-S Pin Layout
ESP32-S Pin-Out

The ESP32-S has a length of 18 mm, a width of 25.5 mm and a height of 2.8 mm ∓ 0.1 mm. Furthermore, it has 38 pins, defined as follows (cf. Datasheet):

The following table shows the name, type, number and function of the pins on the left-side of the ESP32-S:

ESP32-S Pin-Out
NameTypeGPIOFunction
GNDPGround
3V3PPower Supply: 3.3V (VDD), 500 mA
ENIChip-enable Signal (Active high)
SENSOR_VPIADC_H, ADC1_CH0, RTC_GPIO0
SENSOR_VNIADC1_CH3, ADC_H, RTC_GPIO3
IO34IGPIO34ADC1_CH6, RTC_GPIO4
IO35IGPIO35ADC1_CH7, RTC_GPIO5
IO32I/OGPIO32XTAL_32K_P (32.768kHz crystal oscillator input), ADC1_CH4, TOUCH9, RTC_GPIO9
IO33I/OGPIO33XTAL_32K_N (32.768kHz crystal oscillator output), ADC1_CH5, TOUCH8, RTC_GPIO8
IO25I/OGPIO25DAC_1, ADC2_CH8, RTC_GPIO6, EMAC_RXD0
IO26I/OGPIO26DAC_2, ADC2_CH9, RTC_GPIO7, EMAC_RXD1
IO27I/OGPIO27ADC2_CH7, TOUCH7, RTC_GPIO17, EMAC_RX_DV
IO14I/OGPIO14ADC2_CH6, TOUCH6, RTC_GPIO16, MTMS, HSPICLK, HS2_CLK, SD_CLK, EMAC_TXD2
IO12I/OGPIO12ADC2_CH5, TOUCH5, RTC_GPIO15, MTDI, HSPIQ, HS2_DATA2, SD_DATA2, EMAC_TXD3
Mapping of the pins at the left-side of the ESP32-S

The following table shows the name, type, number and function of the pins on the bottom of the ESP32-S:

ESP32-S Pin-Out
NameTypeGPIOFunction
GNDPGround
IO13I/OGPIO13ADC2_CH4, TOUCH4, RTC_GPIO14, MTCK, HSPID, HS2_DATA3, SD_DATA3, EMAC_RX_ER
SHD/SD2I/OGPIO9SD_DATA2, SPIHD, HS1_DATA2, U1RXD
SWP/SD3I/OGPIO10SD_DATA3, SPIWP, HS1_DATA3, U1TXD
SCS/CMDI/OGPIO11SD_CMD, SPICS0, HS1_CMD, U1RTS
SCK/CLKI/OGPIO6SD_CLK, SPICLK, HS1_CLK, U1CTS
SDO/SD0I/OGPIO7SD_DATA0, SPIQ, HS1_DATA0, U2RTS
SDI/SD1I/OGPIO8SD_DATA1, SPID, HS1_DATA1, U2CTS
IO15I/OGPIO15ADC2_CH3, TOUCH3, MTDO, HSPICS0, RTC_GPIO13, HS2_CMD, SD_CMD, EMAC_RXD3
IO2I/OGPIO2ADC2_CH2, TOUCH2, RTC_GPIO12, HSPIWP, HS2_DATA0, SD_DATA0
Mapping of the pins at the botom of the ESP32-S

The following table shows the name, type, number and function of the pins on the right-side of the ESP32-S:

ESP32-S Pin-Out
NameTypeGPIOFunction
IO0I/OGPIO0ADC2_CH1, TOUCH1, RTC_GPIO11, CLK_OUT1, EMAC_TX_CLK
IO4I/OGPIO4ADC2_CH0, TOUCH0, RTC_GPIO10, HSPIHD, HS2_DATA1, SD_DATA1, EMAC_TX_ER
IO16I/OGPIO16HS1_DATA4, U2RXD, EMAC_CLK_OUT
IO17I/OGPIO17HS1_DATA5, U2TXD, EMAC_CLK_OUT_180
IO5I/OGPIO5VSPICS0, HS1_DATA6, EMAC_RX_CLK
IO18I/OGPIO18VSPICLK, HS1_DATA7
IO19I/OGPIO19VSPIQ, U0CTS, EMAC_TXD0
NC
IO21I/OGPIO21VSPIHD, EMAC_TX_EN
RXD0I/OGPIO3U0RXD, CLK_OUT2
TXD0I/OGPIO1U0TXD, CLK_OUT3, EMAC_RXD2
IO22I/OGPIO22VSPIWP, U0RTS, EMAC_TXD1
IO23I/OGPIO23VSPID, HS1_STROBE
GNDPGround
Pin Mapping

Modules and Functions

(coming soon)

Electrical Characteristics

(coming soon)

Schematic Diagram

ESP32-S Schematic Diagram
Schematic Diagram of the ESP32-S (Source)