ESP32S3 Walter Module

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Development Board

Code name: ESP32S3_DEV

ESP32S3 QUICKSPOT

ESP32S3 Walter Module is a development board based on the ESP32S3 microcontroller using XTENSA architecture.

This board features a maximum CPU frequency of 240 MHz and 16MB flash memory.

About ESP32S3 Walter Module

Walter is a small, highly integrated IoT module built to tackle complex connectivity and processing needs. At its core is the ESP32-S3, a versatile system-on-chip (SoC) featuring a dual-core processor with hardware acceleration for machine learning, cryptography, and signal processing. It includes a range of peripherals, such as UART, SPI, I²C, and CAN, alongside built-in Wi-Fi b/g/n and Bluetooth 5, providing robust local networking and communication options.

What sets Walter apart is its inclusion of the Sequans GM02SP modem, offering LTE-M and NB-IoT 5G connectivity for low-power, wide-area communication, ideal for IoT applications. The modem also integrates a GNSS receiver, adding precise positioning capabilities for tasks like asset tracking, navigation, or geolocation.

Technical Specifications

Complete technical specification details for ESP32S3 Walter Module

Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 5.0

BLE 5.0

LTE: CAT M1/NB1/NB2 Yes

Microcontroller

Model esp32s3

Clock Speed 240 MHz

Flash Size 16MB

Architecture xtensa

✨ Features & Pins

Digital IO 24

Analog Input 22

PWM 22

Interrupts 22

• • LTE: CAT M1/NB1/NB2 (GM02SP module)
• • GPS: GPS, GNSS Constellation support (GM02SP module)
• • Ultra low deep sleep current of 9.8µA
• • Certified for CE, FCC, IC, UKCA, New-Zealand and Australia

Download Full Datasheet

Quick Setup

Copy-paste configs for ESP32S3 Walter Module - auto‑generated from this board’s exact hardware specs.

ESP32S3 240 MHz 16MB DIO Xtensa

In Arduino IDE 2 select Esp32s3 Dev from the esp32 by Espressif package. In PlatformIO use board = esp32-s3-devkitm-1. ESP32S3 · 240 MHz · 16MB · DIO.

Arduino IDE PlatformIO ESPHome esptool

Tools menu settings Copy

Board (select in Arduino IDE) Esp32s3 Dev

CPU Frequency 240 MHz

Flash Size 16MB

Flash Mode DIO

Upload Speed 921600

Architecture Xtensa

In Arduino IDE 2, open Boards Manager, search “esp32” by Espressif and install it. Then go to Tools → Board and select “Esp32s3 Dev” for the ESP32S3 Walter Module.

platformio.ini Copy

[env:esp32s3-walter]
platform  = espressif32
board     = esp32-s3-devkitm-1
framework = arduino

; Exact hardware config for ESP32S3 Walter Module
board_build.mcu        = esp32s3
board_build.f_cpu      = 240000000L
board_build.flash_size = 16MB
board_build.flash_mode = dio
board_upload.flash_size = 16MB

The board value is a close generic match - check PlatformIO board registry for an exact fit.

esp32: block (YAML) Copy

esp32:
  board: esp32-s3-devkitc-1
  framework:
    type: arduino   # or "esp-idf"

# ESP32S3 Walter Module - 240 MHz ESP32S3
# Flash: 16MB | USB: N/A

Paste into your device’s .yaml. See ESPHome ESP32 docs for full options.

esptool.py - flash command Copy

esptool.py \
  --chip esp32s3 \
  --baud 921600 \
  write_flash \
    --flash_mode dio \
    --flash_size 16MB \
    0x0 bootloader.bin \
    0x8000    partitions.bin \
    0xe000    boot_app0.bin \
    0x10000   firmware.bin

Install: pip install esptool - replace firmware.bin with your binary - bootloader at 0x0

ESP32S3 Walter Module Pinout Diagram

Complete pin reference for ESP32S3 Walter Module

Safe Pins to Use

These pins are safe for general GPIO usage without boot or system conflicts

RESET

IO44/RX0

IO43/TX0

DFU/3V3 EN

IO2

IO1

IO4

IO5

IO6

IO7

IO15

IO16

IO17

IO18

IO8

3V3 OUT

VIN

Why Are These Pins Safe?

✓ No boot sequence involvement

✓ No flash/PSRAM connections

✓ No USB or JTAG conflicts

✓ Freely assignable without issues

Pins to Avoid or Use with Caution

Reserved for critical functions. Misuse may cause boot failures, programming issues, or system conflicts.

Strapping Pins

Boot behavior & flash voltage

JTAG Debugging

Low-level debugging interface

USB Pins

USB Serial/JTAG communication

Flash/SPI Pins

Memory & PSRAM connections

UART Serial

Debugging & firmware uploads

PIN

Label

Why Avoid

Type

IO12

FSPICLK

Drives the flash (and PSRAM) clock. This critical signal must be reserved for memory and not used as general GPIO.

⚡ Flash

IO11

FSPID

Used as a data line for flash (and in-package PSRAM). It should not be used as GPIO when the flash/PSRAM is in use.

⚡ Flash

IO13

FSPIQ

Used as a data line for flash/PSRAM transfers. Not available for other uses when flash/PSRAM is connected.

⚡ Flash

IO38

FSPIWP

On flash-equipped chips, this pin is tied to the flash’s WP# (or D3) line. It should be avoided for other use, as it’s needed for flash operations.

⚡ Flash

IO39

MTCK (GPIO39)

Default JTAG debugging TCK pin. If JTAG is needed, this pin must be free; it may also be used internally for PSRAM chip select on certain modules, so avoid repurposing it.

🪛 Other

IO40

MTDO (GPIO40)

Default JTAG TDO output for debugging. Using it as GPIO will interfere with JTAG debugging functionality.

🪛 Other

IO41

MTDI (GPIO41)

Default JTAG TDI input for debugging. Should be reserved for JTAG or left unused if JTAG is to remain available.

🪛 Other

IO42

MTMS (GPIO42)

Default JTAG TMS signal for debugging. Using this pin for other purposes will disable the JTAG interface (unless JTAG is rerouted to USB).

🪛 Other

IO9

FSPIHD

Connected to external flash (data/hold signal) on most modules. Not recommended for use as GPIO, since it must remain dedicated to flash communication.

⚡ Flash

IO10

FSPICS0

Used to select the external flash chip. It is required for flash access and cannot be repurposed without losing flash connectivity

⚡ Flash

Show All 10 Pins

Useful Links

Datasheets and resources for ESP32S3 Walter Module

[

Board Datasheet

Technical specifications

](https://www.quickspot.io/datasheet/walter_datasheet.pdf)[

ESP32S3 Datasheet

Microcontroller reference

](https://www.espressif.com/sites/default/files/documentation/esp32-s3_datasheet_en.pdf)

ESP32S3 Walter Module Custom Pin Mapping

Pin configuration and GPIO mapping for ESP32S3 Walter Module

24

Digital I/O Pins

22

Interrupt Pins

22

Analog Inputs

22

PWM Pins

Pin

Function

ESP Pin

I/O Type

Description

1

RESET

EN

input

ESP32 reset with 10k pullup

2

IO44/RX0

RXD0

bidirectional

ESP32 UART0 Receive

3

IO43/TX0

TXD0

bidirectional

ESP32 UART0 Transmit

4

DFU/3V3 EN

IO0

bidirectional

DFU when low on boot and 3V3 output enable

5

IO12

IO12

bidirectional

General purpose I/O

6

IO11

IO11

bidirectional

General purpose I/O

7

IO13

IO13

bidirectional

General purpose I/O

8

IO38

IO38

bidirectional

General purpose I/O

9

IO39

IO39

bidirectional

General purpose I/O

10

IO40

IO40

bidirectional

General purpose I/O

11

IO41

IO41

bidirectional

General purpose I/O

12

IO42

IO42

bidirectional

General purpose I/O

13

IO2

IO2

bidirectional

General purpose I/O

14

IO1

IO1

bidirectional

General purpose I/O

15

IO4

IO4

bidirectional

General purpose I/O

16

IO5

IO5

bidirectional

General purpose I/O

17

IO6

IO6

bidirectional

General purpose I/O

18

IO7

IO7

bidirectional

General purpose I/O

19

IO15

IO15

bidirectional

General purpose I/O

20

IO16

IO16

bidirectional

General purpose I/O

21

IO17

IO17

bidirectional

General purpose I/O

22

IO18

IO18

bidirectional

General purpose I/O

23

IO8

IO8

bidirectional

General purpose I/O

24

IO9

IO9

bidirectional

General purpose I/O

25

IO10

IO10

bidirectional

General purpose I/O

26

3V3 OUT

N/A

power output

Switchable 3.3VDC output

27

GND

GND

power ground

GND connection

28

VIN

N/A

power input

DC Power input port

Legend

Function Pin role

GPIO ESP32 pin

I/O Direction

# Pin number

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