WeMos LOLIN ESP32 C3 pico: high-resolution pinout and specs

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WeMos LOLIN ESP32 C3 pico pinout low resolution
WeMos LOLIN ESP32 C3 pico pinout low resolution

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One of my preferred manufacturers is WeMos, here is an entry-level development board based on ESP32-C3-WROOM-02, a general-purpose module with 4 MB SPI flash. This board integrates complete Wi-Fi and Bluetooth LE functions.

Key ComponentDescription
ESP32-C3ESP32-C3-WROOM-02 from Espressif is a powerful and general-purpose module that offers Wi-Fi and Bluetooth LE coexistence. It has 4 MB SPI flash.
5 V to 3.3 V LDOPower regulator that converts a 5 V supply into a 3.3 V output.
5 V Power On LEDTurns on when the USB power is connected to the board.
Pin HeadersAll available GPIO pins (except for the SPI bus for flash) are broken out to the pin headers on the board.
Boot ButtonDownload button. Holding down Boot and then pressing Reset initiates Firmware Download mode for downloading firmware through the serial port.
Micro-USB PortUSB interface. Power supply for the board as well as the communication interface between a computer and the ESP32-C3 chip.
Reset ButtonPress this button to restart the system.
USB-to-UART BridgeSingle USB-to-UART bridge chip provides transfer rates up to 3 Mbps.
LEDRGB_LED, driven by GPIO7
Battery connectorPH-2.0 Battery port with 500mA charging
I2C connectorJST SH, 1mm pitch I2C port


UART (Universal Asynchronous Receiver-Transmitter) pins:

  • U0RXD (GPIO20): This pin serves as the UART0 receive (RX) pin, which is used for receiving serial data.
  • U0TXD (GPIO21): This pin serves as the UART0 transmit (TX) pin, which is used for transmitting serial data.

I2C (Inter-Integrated Circuit) pins: The ESP32-C3 does not have dedicated I2C pins. However, you can implement software-based I2C (bit-banging) using any available GPIO pins. It has a JST SH, 1mm pitch I2C port to use for connecting a series of devices.

Battery charging led: by soldering the footprint on the bottom, you can enable a led that show when the device is in charge.

Battery connector: PH-2.0 Battery port with 500mA charging.


CPU and Memory

  • 32-bit RISC-V single-core processor, up to 160
  • CoreMark® score:
    • 1 core at 160 MHz: 407.22 CoreMark; 2.55
  • 384 KB ROM
  • 400 KB SRAM (16 KB for cache)
  • 8 KB SRAM in RTC
  • Embedded flash (see details in Chapter 1
    ESP32-C3 Series Comparison)
  • SPI, Dual SPI, Quad SPI, and QPI interfaces that
    allow connection to multiple external flash
  • Access to flash accelerated by cache
  • Supports flash in-Circuit Programming (ICP)
Ordering CodeEmbedded FlashAmbient Temperature (°C)Package (mm)GPIO No.
ESP32-C3No–40 ∼ 105QFN32 (5*5)22
ESP32-C3FN44 MB–40 ∼ 85QFN32 (5*5)22
ESP32-C3FH44 MB–40 ∼ 105QFN32 (5*5)22
ESP32-C3FH4AZ4 MB–40 ∼ 105QFN32 (5*5)16

Advanced Peripheral Interfaces

  • 22 or 16 programmable GPIOs
  • Digital interfaces:
    • 3 × SPI
    • 2 × UART
    • 1 × I2C
    • 1 × I2S
    • Remote control peripheral, with 2 transmit
      channels and 2 receive channels
    • LED PWM controller, with up to 6 channels
    • Full-speed USB Serial/JTAG controller
    • General DMA controller (GDMA), with 3
      transmit channels and 3 receive channels
    • 1 × TWAI® controller compatible with ISO
      11898-1 (CAN Specification 2.0)
  • Analog interfaces:
    • 2 × 12-bit SAR ADCs, up to 6 channels
    • 1 × temperature sensor
  • Timers:
    • 2 × 54-bit general-purpose timers
    • 3 × digital watchdog timers
    • 1 × analog watchdog timer
    • 1 × 52-bit system timer
  • PH-2.0 Battery port with 500mA charging
  • JST SH, 1mm pitch I2C port


  • IEEE 802.11 b/g/n-compliant
  • Supports 20 MHz, 40 MHz bandwidth in 2.4
    GHz band
  • 1T1R mode with data rate up to 150 Mbps
  • 4 × virtual Wi-Fi interfaces
  • 802.11mc FTM


  • Bluetooth LE: Bluetooth 5, Bluetooth mesh
  • High power mode (21 dBm)
  • Speed: 125 Kbps, 500 Kbps, 1 Mbps, 2 Mbps
  • Advertising extensions
  • Multiple advertisement sets
  • Channel selection algorithm #2
  • Internal co-existence mechanism between Wi-Fi
    and Bluetooth to share the same antenna


  • Secure boot
  • Flash encryption
  • 4096-bit OTP, up to 1792 bits for use
  • Cryptographic hardware acceleration:
    • AES-128/256 (FIPS PUB 197)
  • Permission Control
  • SHA Accelerator (FIPS PUB 180-4)
  • RSA Accelerator
  • Random Number Generator (RNG)
  • HMAC
  • Digital signature

Low Power Management

  • Power Management Unit with four power modes

How to

  1. ESP32: pinout, specs and Arduino IDE configuration
  2. ESP32: integrated SPIFFS Filesystem
  3. ESP32: manage multiple Serial and logging
  4. ESP32 practical power saving
    1. ESP32 practical power saving: manage WiFi and CPU
    2. ESP32 practical power saving: modem and light sleep
    3. ESP32 practical power saving: deep sleep and hibernation
    4. ESP32 practical power saving: preserve data, timer and touch wake up
    5. ESP32 practical power saving: external and ULP wake up
    6. ESP32 practical power saving: UART and GPIO wake up
  5. ESP32: integrated LittleFS FileSystem
  6. ESP32: integrated FFat (Fat/exFAT) FileSystem
  7. ESP32-wroom-32
    1. ESP32-wroom-32: flash, pinout, specs and IDE configuration
  8. ESP32-CAM
    1. ESP32-CAM: pinout, specs and Arduino IDE configuration
    2. ESP32-CAM: upgrade CamerWebServer with flash features
  9. ESP32: use ethernet w5500 with plain (HTTP) and SSL (HTTPS)
  10. ESP32: use ethernet enc28j60 with plain (HTTP) and SSL (HTTPS)
  11. How to use SD card with esp32
  12. esp32 and esp8266: FAT filesystem on external SPI flash memory
  1. Firmware and OTA update management
    1. Firmware management
      1. ESP32: flash compiled firmware (.bin)
      2. ESP32: flash compiled firmware and filesystem (.bin) with GUI tools
    2. OTA update with Arduino IDE
      1. ESP32 OTA update with Arduino IDE: filesystem, firmware, and password
    3. OTA update with Web Browser
      1. ESP32 OTA update with Web Browser: firmware, filesystem, and authentication
      2. ESP32 OTA update with Web Browser: upload in HTTPS (SSL/TLS) with self-signed certificate
      3. ESP32 OTA update with Web Browser: custom web interface
    4. Self OTA uptate from HTTP server
      1. ESP32 self OTA update firmware from the server
      2. ESP32 self OTA update firmware from the server with version check
      3. ESP32 self-OTA update in HTTPS (SSL/TLS) with trusted self-signed certificate
    5. Non-standard Firmware update
      1. ESP32 firmware and filesystem update from SD card
      2. ESP32 firmware and filesystem update with FTP client
  1. Integrating LAN8720 with ESP32 for Ethernet Connectivity with plain (HTTP) and SSL (HTTPS)
  2. Connecting the EByte E70 to ESP32 c3/s3 devices and a simple sketch example
  3. ESP32-C3: pinout, specs and Arduino IDE configuration


ESP32c3 datasheet

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Board Schematic

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PCB size

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