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Espressif ESP32-C3-AWS-ExpressLink-DevKit
ESP32-C3 dev board with AWS ExpressLink - simplifies secure cloud connectivity for IoT products.
ESP32-C3
RISC-V MCU
160MHz
clock
4MB
flash
400KB
SRAM
22· 5 ADC
GPIO
BLE 5.0+ WiFi
radio
Pinout
22 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | A0PWM | safe | adc | |
| 2 | 1 | A1PWM | safe | adc | |
| 3 | 2 | A2PWM | strapping | adc | |
| 4 | 3 | A3PWM | safe | adc | |
| 5 | 4 | A4PWM | strapping | adc | |
| 6 | 5 | PWM | strapping | - | |
| 7 | 6 | PWM | strapping | - | |
| 8 | 7 | PWM | strapping | - | |
| 9 | 8 | PWM | strapping | - | |
| 10 | 9 | PWM | strapping | - | |
| 11 | 10 | PWM | safe | - | |
| 12 | 11 | PWM | strapping | - | |
| 13 | 12 | PWM | strapping | - | |
| 14 | 13 | PWM | strapping | - | |
| 15 | 14 | PWM | strapping | - | |
| 16 | 15 | PWM | strapping | - | |
| 17 | 16 | PWM | strapping | - | |
| 18 | 17 | PWM | strapping | - | |
| 19 | 18 | PWM | uart | - | |
| 20 | 19 | PWM | uart | - | |
| 21 | 20 | PWM | uart | - | |
| 22 | 21 | PWM | uart | - |
Start with these
4 pins with no boot or system involvementA0PWMA1PWMA3PWMPWM
Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| A2 | GPIO2 | Must be held high during boot (if low on reset, normal flash boot may fail) | Strapping |
| A4 | MTMS | Used during boot; JTAG TMS for debugging; acts as Quad-SPI flash IO (hold data line) in internal-flash variants | JTAG |
| PWM | MTDI | Used during boot; JTAG TDI for debugging; acts as Quad-SPI flash IO (write-protect data line) in internal-flash variants | JTAG |
| PWM | MTCK | Used during boot; JTAG TCK for debugging; provides flash clock in internal-flash variants | JTAG |
| PWM | MTDO | Used during boot; JTAG TDO for debugging; acts as Quad-SPI flash IO (data line) in internal-flash variants | JTAG |
| PWM | GPIO8 | Must be held high during reset (if low, UART flashing/boot may not work) | Strapping |
| PWM | GPIO9 | Controls boot mode on reset (HIGH for normal flash boot, LOW enters serial download mode) | Strapping |
| PWM | U0RXD | Used as UART0 receive (console/bootloader); repurposing may disable serial programming and debug logs | UART |
| PWM | U0TXD | Used as UART0 transmit (console/bootloader); repurposing may disable serial console output and printing | UART |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| PWM | VDD_SPI | By default powers the SPI flash; only configurable as GPIO if the flash is powered externally (not recommended otherwise) | Flash |
| PWM | SPIHD | Connected to flash HOLD#; not recommended for other use as it’s reserved for flash communication | Flash |
| PWM | SPIWP | Connected to flash WP#; not recommended for other use (used to interface with SPI flash) | Flash |
| PWM | SPICS0 | Dedicated chip-select for SPI flash memory; cannot be repurposed for general I/O | Flash |
| PWM | SPICLK | Dedicated clock line for SPI flash; cannot be used as general GPIO without interfering with flash | Flash |
| PWM | SPID | Used for SPI flash data transfer (data-out from flash); not available for other functions | Flash |
| PWM | SPIQ | Used for SPI flash data transfer (data-in to flash); not available for other functions | Flash |
| PWM | USB_D- | By default connected to on-chip USB Serial/JTAG controller; to use as GPIO it must be reconfigured from its USB function | USB |
| PWM | USB_D+ | By default connected to on-chip USB Serial/JTAG controller; not available for GPIO use unless USB functionality is disabled or remapped | USB |
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes All 22 pins on the Espressif ESP32-C3-AWS-ExpressLink-DevKit are usable GPIO. Beyond plain digital I/O you get 5 ADC-capable pins for sensors and battery…
All 22 pins on the Espressif ESP32-C3-AWS-ExpressLink-DevKit are usable GPIO.
Beyond plain digital I/O you get 5 ADC-capable pins for sensors and battery monitoring.
9 of the exposed pins carry boot-time or system duties on the ESP32-C3 (A2, A4, PWM and 6 more) - check the guidance above before wiring anything to them. A0, A1, A3 and PWM are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Serial chip: onboard. Not detected? Hold BOOT while plugging in.
2
Flash with your tool
Arduino IDE, PlatformIO, ESPHome or esptool - copy the settings on the right.
3
Verify it runs
The blink example uses GPIO0 - swap for your board's LED pin if different.
Board: Esp32 C3 Aws Expresslink Devkit
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(0, OUTPUT);
digitalWrite(0, LOW); // on (often inverted)[env:esp32-c3-aws-expresslink-devkit]
platform = espressif32
board = esp32-c3-devkitm-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32-c3-devkitm-1
variant: esp32_c3_aws_expresslink_devkit
framework:
type: esp-idf
# blink - GPIO0
output:
- platform: gpio
pin: 0
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32c3 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binBuild details: sketch space 1310720 B · data 327680 B · DIO
Specifications
ESP32-C3Compute
MCU
ESP32-C3 · RISC-V
Clock
160 MHz
SRAM · Flash
400 KB · 4MB
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
5.0 LE
Antenna
PCB
I/O
GPIO · ADC
22 · 5
UART · I²C · SPI
2 · 1 · 3
PWM
6 channels
Power
USB
Micro-USB
Serial
-
Boot address
0x0
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.25 MB · 320 KB
The Espressif ESP32-C3-AWS-ExpressLink-DevKit uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO boot mode. The maximum sketch size is 1.25 MB with 320 KB available for data.
About this board
Inside sits the ESP32-C3 - a single-core RISC-V and the budget low-power pick.
The $10.00 price tag is typical for an ESP32-C3 board.
With 22 GPIO broken out, you get more pins to play with than most ESP32-C3 boards offer.
Around the module: status LEDs (Power, RGB) and Reset buttons.
The ESP32-C3-AWS-ExpressLink-DevKit is a development board that hosts Espressif's AWS IoT ExpressLink module, based on the ESP32-C3-MINI-1-N4-A. It provides out-of-the-box, seamless AWS IoT connectivity for external host MCUs through a simple serial interface, transforming offline products into cloud-connected devices. The module handles complex tasks such as authentication, device management, connectivity, messaging, and OTA updates, relieving developers from maintaining complex firmware and providing end-to-end security and fleet management at scale.
Where to buy
prices are typical street pricesAs an Amazon Associate, ESPboards earns from qualifying purchases.
Resources
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