LaskaKit ESP32-C3-LPKit is a low-power D1 mini-sized board with the ESP32-C3 chip and native USB-C. It has a cell charger, battery measurement, an RGB LED and μŠup connectors for both I2C and SPI. The sensor power (VSENSOR) can be switched off, so the board lasts a long time on battery in deep sleep.
Specifications
- ESP32-C3 (ESP32-C3-MINI-1-N4 module): RISC-V 160 MHz, 4 MB flash
- Wi-Fi, Bluetooth LE 5
- 2 headers of 8 pins (D1 mini layout), μŠup I2C and μŠup SPI
- switchable VSENSOR sensor power (GPIO4), battery measurement (GPIO0), SK6812 RGB LED (GPIO9)
- TP4054 charger (0.4 A), native USB-C (no converter)
- 36 × 25 mm
The pinout applies to version 4.0 and is based on the LaskaKit schematic and Gerbers. Version 3.x had different pins on the left header (A0, IO3, always-on 3.3 V) – check the silkscreen against the version on your board.
The pin labeled “+3V3” on the left header is actually VSENSOR – it has voltage only when GPIO4 is at logic 1. The μŠup SPI connector (J1) has pins 1 GND, 2 VSENSOR, 3 MISO (GPIO2), 4 CLK (GPIO6), 5 MOSI (GPIO7), 6 CS (GPIO3); in the table they are listed as J1-1 to J1-6.
Pinout and pin table
Hover over a pin in the diagram or a table row; use the filter to highlight a bus. You can download the pinout as PNG or SVG.
| Pin | Name | Direction | UART | I2C | SPI | ADC | Note |
|---|---|---|---|---|---|---|---|
| J1-1 | GND | – | |||||
| J1-2 | VSENSOR | output | Silkscreened "+3V3", actually VSENSOR: power for both μŠup connectors and the RGB LED from the second regulator, enabled by GPIO4 (logic 1). There is no always-on 3.3 V on the headers. | ||||
| J1-3 | GPIO2 | input/output | MISO | ADC1_CH2 | SPI MISO. Strapping pin – do not hold at logic 0 at boot | ||
| J1-4 | GPIO6 | input/output | SCK | JTAG MTCK | |||
| J1-5 | GPIO7 | input/output | MOSI | JTAG MTDO | |||
| J1-6 | GPIO3 | input/output | SS | ADC1_CH3 | |||
| Left header 1 | EN | input | Reset (RESET button) – logic 0 holds the chip in reset | ||||
| Left header 2 | GPIO3 | input/output | SS | ADC1_CH3 | |||
| Left header 3 | GPIO2 | input/output | MISO | ADC1_CH2 | SPI MISO. Strapping pin – do not hold at logic 0 at boot | ||
| Left header 4 | GPIO1 | input/output | ADC1_CH1 | ||||
| Left header 5 | GPIO0 | input/output | ADC1_CH0 | Battery measurement: the 1 MΩ / 1.3 MΩ divider (Vbat = Vadc × 1.769) is factory-connected via jumpers ADC_IO0 and ADC-BATT. To use the pin for something else, cut the ADC_IO0 jumper. | |||
| Left header 6 | GPIO4 | input/output | ADC1_CH4 | Sensor power enable VSENSOR (logic 1 = on) | |||
| Left header 7 | GPIO5 | input/output | ADC2_CH0 | JTAG MTDI | |||
| Left header 8 | VSENSOR | output | Silkscreened "+3V3", actually VSENSOR: power for both μŠup connectors and the RGB LED from the second regulator, enabled by GPIO4 (logic 1). There is no always-on 3.3 V on the headers. | ||||
| Right header 1 | GPIO21 | input/output | TX | ||||
| Right header 2 | GPIO20 | input/output | RX | ||||
| Right header 3 | GPIO10 | input/output | SCL | I2C SCL (also on μŠup I2C). | |||
| Right header 4 | GPIO8 | input/output | SDA | I2C SDA (also on μŠup I2C). Strapping pin with a 10 kΩ pull-up. I2C pull-ups to VSENSOR are connected by the I2C_PULLUPS jumper (open from the factory). | |||
| Right header 5 | GPIO7 | input/output | MOSI | JTAG MTDO | |||
| Right header 6 | GPIO6 | input/output | SCK | JTAG MTCK | |||
| Right header 7 | GND | – | |||||
| Right header 8 | VIN | input/output | Power input 3.5–5.5 V. With USB connected the pin carries 5 V from USB (after the reverse-current transistor). | ||||
| μŠup I2C 1 | GND | – | |||||
| μŠup I2C 2 | VSENSOR | output | Silkscreened "+3V3", actually VSENSOR: power for both μŠup connectors and the RGB LED from the second regulator, enabled by GPIO4 (logic 1). There is no always-on 3.3 V on the headers. | ||||
| μŠup I2C 3 | GPIO8 | input/output | SDA | I2C SDA (also on μŠup I2C). Strapping pin with a 10 kΩ pull-up. I2C pull-ups to VSENSOR are connected by the I2C_PULLUPS jumper (open from the factory). | |||
| μŠup I2C 4 | GPIO10 | input/output | SCL | I2C SCL (also on μŠup I2C). | |||
| Battery 1 | BAT+ | input/output | 3.7 V Li-Ion / Li-Pol cell (charged by TP4054) | ||||
| Battery 2 | GND | – |
Pins used on the board
These chip pins are used by parts on the board and are not broken out:
| Pin | Function on the board |
|---|---|
| GPIO9 | FLASH button and SK6812 RGB LED data (strapping pin, 10k pull-up; the LED lights only with VSENSOR on) |
| GPIO18, 19 | USB D− and D+ (native USB, USB-C) |
What to watch out for
- The GPIO are not 5V tolerant.
- Neither the sensors on μŠup nor the RGB LED work until GPIO4 turns on the VSENSOR power.
- The “+3V3” pin on the left header is the switchable VSENSOR – there is no always-on 3.3 V on the headers.
- A battery divider is connected to GPIO0 from the factory – for other uses, cut the ADC_IO0 solder jumper.
- GPIO2, 8 and 9 are strapping pins; GPIO9 is the FLASH button and the RGB LED data line.
ESP32-C3 on chiptron.eu/
Projects and guides on chiptron.eu/:
- ESP32 chip comparison – when to choose the C3 and when another chip
More pinouts
See all pinouts on the Pinouts page.