ESP32-WROOM Development Board

Code name: ESP32_WROOM_DA

ESP32-WROOM development board is based on esp32 microcontroller and uses xtensa architecture. This board has a maximum CPU frequency of 240 MHz and a flash size of 4MB.

⚡ Tech Specs 📌 Pinout 🔗 Useful Links 🗺️ Mappings 🛠️ Tools

About ESP32-WROOM

The ESP32-WROOM-32 is a versatile and powerful Wi-Fi + Bluetooth® + Bluetooth LE module, designed to support a wide range of applications. It is equally suitable for low-power sensor networks as well as high-demand tasks like voice encoding, music streaming, and MP3 decoding.

At the heart of the module is the ESP32-D0WDQ6 chip, engineered for scalability and adaptability. This chip features two CPU cores that can be independently controlled, with an adjustable clock frequency ranging from 80 MHz to 240 MHz. Additionally, it includes a low-power coprocessor, which is ideal for handling tasks that require minimal computing power—such as peripheral monitoring—while conserving energy.

The ESP32 integrates a rich set of peripherals, including capacitive touch sensors, an SD card interface, Ethernet, high-speed SPI, UART, I2S, and I2C. Its combination of power, flexibility, and connectivity makes the ESP32-WROOM-32 a perfect choice for a broad spectrum of IoT and embedded applications.

Technical Specifications

🛰️ Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 4.2

BLE 4.2

🧠 Microcontroller

Model esp32

Clock Speed 240 MHz

Flash Size 4MB

Architecture xtensa

✨ Features

40 digital IO pins
16 external interrupt pins
16 analog input pins
19 PWM pins

View Full Datasheet

ESP32-WROOM Pinout

The ESP32-WROOM pinout is designed to offer developers a highly versatile and feature-packed layout for a variety of IoT and embedded applications. The ESP32 WROOM includes essential power pins such as 5V, 3.3V, and GND, ensuring stable power delivery for external components. Key communication protocols are well-supported, with pins for UART (RXD0, TXD0), SPI (MISO, MOSI, SCK, and SS), and I2C (SDA and SCL) to interface with a wide range of peripherals.

The ESP32 WROOM Devkit also supports multiple ADC pins (IO34, IO35, IO36, etc.), making it ideal for projects that require analog input, such as reading sensor data. Additionally, specialized pins such as DAC (IO25, IO26) and Touch Pins enhance its usability in advanced applications. The inclusion of RTC GPIOs further adds low-power features, allowing developers to take full advantage of the ESP32-WROOM pinout for efficient power management.

✅ Safe Pins to Use

For general GPIO usage, these are the safest and most flexible choices:

🔹 SENSOR_VP

🔹 SENSOR_VN

🔹 IO32

🔹 IO33

🔹 IO25

🔹 IO26

🔹 IO27

🔹 SHD/SD2

🔹 SWP/SD3

🔹 SCS/CMD

🔹 SCK/CLK

🔹 SDO/SD0

🔹 SDI/SD1

🔹 IO18

🔹 IO19

🔹 NC

🔹 IO21

🔹 RXD0

🔹 TXD0

🔹 IO22

🔹 IO23

Why Are These Pins Safe?

Not involved in bootstrapping → No impact on device boot mode or system startup
Not linked to flash memory or PSRAM → Won't interfere with storage or memory access
Not dedicated to USB or JTAG → Free for general use without affecting debugging
No special hardware connections → Freely assignable without internal conflicts

⚠️ Pins to Avoid or Use with Caution

Some pins are reserved for critical functions like bootstrapping, JTAG debugging, USB communication, and flash memory operations. Misusing these pins may lead to boot failures, programming issues, USB conflicts, or disruptions in flash storage.

Critical Pin Categories:

🛠️ Strapping Pins: Control boot behavior and flash voltage selection
🔗 JTAG Debugging Pins: Required for low-level debugging
🔌 USB Communication Pins: Used for USB Serial/JTAG communication
⚡ Flash Memory & SPI Pins: Connected to SPI flash memory and PSRAM
📡 UART Serial Communication Pins: Used for debugging and firmware uploads

PIN	Label	Reason	Function
IO34	GPIO34	Cannot be used as output (no drive capability); only suitable for analog/digital input.	🪛 Other
IO35	GPIO35	Cannot be used as output; only suitable for input.	🪛 Other
IO14	MTMS (GPIO14)	Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.	🪛 Other
IO12	MTDI (GPIO12)	Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.	🛠️ Strapping
IO13	MTCK (GPIO13)	Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.	🪛 Other
IO15	MTDO (GPIO15)	Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.	🛠️ Strapping
IO2	GPIO2	If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.	🛠️ Strapping
IO0	GPIO0	Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.	🛠️ Strapping
IO4	GPIO4	Sampled at reset for boot config; should not be driven at boot (affects boot mode timing).	🛠️ Strapping
IO16	GPIO16	Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules.	⚡ Flash
IO17	GPIO17	Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules.	⚡ Flash
IO5	GPIO5	Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.	🛠️ Strapping

ESP32-WROOM Useful Links

🔗 Datasheet

https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf

🔗 ESP32 Datasheet

https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf

ESP32-WROOM Pin Mappings

This development board provides 40 digital IO pins, out of which 16 can be used as external interrupt pins , 16 as analog input pins and 19 pins have Pulse-Width Modulation (PWM) .

Pin	Function	ESP Pin	Input/Output	Description
1	SENSOR_VP	GPIO36	input	ADC1_CH0, RTC_GPIO0
2	SENSOR_VN	GPIO39	input	ADC1_CH3, RTC_GPIO3
3	IO34	GPIO34	input	ADC1_CH6, RTC_GPIO4
4	IO35	GPIO35	input	ADC1_CH7, RTC_GPIO5
5	IO32	GPIO32	bidirectional	XTAL_32K_P (32.768 kHz crystal oscillator input), ADC1_CH4, TOUCH9, RTC_GPIO9
6	IO33	GPIO33	bidirectional	XTAL_32K_N (32.768 kHz crystal oscillator output), ADC1_CH5, TOUCH8, RTC_GPIO8
7	IO25	GPIO25	bidirectional	DAC_1, ADC2_CH8, RTC_GPIO6, EMAC_RXD0
8	IO26	GPIO26	bidirectional	DAC_2, ADC2_CH9, RTC_GPIO7, EMAC_RXD1
9	IO27	GPIO27	bidirectional	ADC2_CH7, TOUCH7, RTC_GPIO17, EMAC_RX_DV
10	IO14	GPIO14	bidirectional	ADC2_CH6, TOUCH6, RTC_GPIO16, MTMS, HSPICLK, HS2_CLK, SD_CLK, EMAC_TXD2
11	IO12	GPIO12	bidirectional	ADC2_CH5, TOUCH5, RTC_GPIO15, MTDI, HSPIQ, HS2_DATA2, SD_DATA2, EMAC_TXD3
12	GND	N/A	power ground	Ground connection
13	IO13	GPIO13	bidirectional	ADC2_CH4, TOUCH4, RTC_GPIO14, MTCK, HSPID, HS2_DATA3, SD_DATA3, EMAC_RX_ER
14	SHD/SD2	GPIO9	bidirectional	SD_DATA2, SPIHD, HS1_DATA2, U1RXD
15	SWP/SD3	GPIO10	bidirectional	SD_DATA3, SPIWP, HS1_DATA3, U1TXD
16	SCS/CMD	GPIO11	bidirectional	SD_CMD, SPICS0, HS1_CMD, U1RTS
17	SCK/CLK	GPIO6	bidirectional	SD_CLK, SPICLK, HS1_CLK, U1CTS
18	SDO/SD0	GPIO7	bidirectional	SD_DATA0, SPIQ, HS1_DATA0, U2RTS
19	SDI/SD1	GPIO8	bidirectional	SD_DATA1, SPID, HS1_DATA1, U2CTS
20	IO15	GPIO15	bidirectional	ADC2_CH3, TOUCH3, MTDO, HSPICS0, RTC_GPIO13, HS2_CMD, SD_CMD, EMAC_RXD3
21	IO2	GPIO2	bidirectional	ADC2_CH2, TOUCH2, RTC_GPIO12, HSPIWP, HS2_DATA0, SD_DATA0
22	IO0	GPIO0	bidirectional	ADC2_CH1, TOUCH1, RTC_GPIO11, CLK_OUT1, EMAC_TX_CLK
23	IO4	GPIO4	bidirectional	ADC2_CH0, TOUCH0, RTC_GPIO10, HSPIHD, HS2_DATA1, SD_DATA1, EMAC_TX_ER
24	IO16	GPIO16	bidirectional	HS1_DATA4, U2RXD, EMAC_CLK_OUT
25	IO17	GPIO17	bidirectional	HS1_DATA5, U2TXD, EMAC_CLK_OUT_180
26	IO5	GPIO5	bidirectional	VSPICS0, HS1_DATA6, EMAC_RX_CLK
27	IO18	GPIO18	bidirectional	VSPICLK, HS1_DATA7
28	IO19	GPIO19	bidirectional	VSPIQ, U0CTS, EMAC_TXD0
29	NC	N/A	not connected	No connection
30	IO21	GPIO21	bidirectional	VSPIHD, EMAC_TX_EN
31	RXD0	GPIO3	bidirectional	U0RXD, CLK_OUT2
32	TXD0	GPIO1	bidirectional	U0TXD, CLK_OUT3, EMAC_RXD2
33	IO22	GPIO22	bidirectional	VSPIWP, U0RTS, EMAC_TXD1
34	IO23	GPIO23	bidirectional	VSPID, HS1_STROBE
35	GND	N/A	power ground	Ground connection

Function Pin Function

ESP Pin Pin on ESP32

I/O Input/Output Pin

Description Pin Description

ESP32-WROOM Pins Mapping Arduino IDE

Below you can find the ESP32-WROOM pinout. This development board provides 40 digital IO pins, out of which 16 can be used as external interrupt pins, 16 as analog input pins and 19 pins have Pulse-Width Modulation (PWM).

Pin	Analog	Touch	PWM	Other
0	A11	T1
1			PWM	TX
2	A12	T2	PWM	ANT1
3			PWM	RX
4	A10	T0	PWM
5			PWM	SS
12	A15	T5	PWM
13	A14	T4	PWM
14	A16	T6	PWM
15	A13	T3	PWM
18			PWM	SCK
19			PWM	MISO
21			PWM	SDA
22			PWM	SCL
23			PWM	MOSI
25	A18		PWM	DAC1 ANT2
26	A19		PWM	DAC2
27	A17	T7	PWM
32	A4	T9	PWM
33	A5	T8	PWM
34	A6
35	A7
36	A0
39	A3

Analog Analog input pins

Touch Touch pins

Function Function pins

RX / TX Receive/Transmit

LED_BUILTIN Built-in LED

PWM Pulse-Width Modulation

Default Tools

Bootloader tool	esptool_py
Uploader tool	esptool_py
Network uploader tool	esp_ota
Bootloader address	0x1000
Flash mode	dio
Boot mode	dio
Maximum upload size	1280 Kb (1310720 B)
Maximum data size	320 Kb (327680 B)

The ESP32-WROOM development board by default uses esptool_py uploader tool, esp_ota network uploader tool for Over-the-air (OTA) uploads and esptool_py bootloader tool. The bootloader starts at address "0x1000". Flash mode and boot mode for ESP32-WROOM development board by default is dio and dio respectively.