Boardlolin

LOLIN C3 mini

LOLIN/WEMOS C3 mini: a 34.3 x 25.4 mm ESP32-C3FH4 board (RISC-V 160 MHz, 4 MB in-package flash) with 12 GPIO on 16 edge pads in two columns (J2 left: EN/3/2/1/0/4/5/3V3; J3 right: TX/RX/10/8/7/6/GND/VBUS; silkscreen uses bare GPIO numbers), one WS2812B RGB LED, USB Type-C, download mode via Button 9 + Reset, 3.3 V logic and D1-mini-shield compatibility. Current schematic V2.1.0. Not the 'C3 SuperMini'.

Assembly & compatibility

Main chip: ESP32-C3

Revisions

V1.0.0 (previous) — Previous revision; keep scope-limited claims. · LOLIN C3 mini product page (features, technical specs, schematic V2.1.0 link) · Version section: 'V1.0.0'
V2.1.0 (current) — Current schematic sch_c3_mini_v2.1.0.pdf. · LOLIN C3 mini product page (features, technical specs, schematic V2.1.0 link) · Version section: 'V2.1.0 latest'

Pinout

power · ground · GPIO / signal · onboard LED

Left edge column in the official pin image view (USB pointing down): EN / 3 / 2 / 1 / 0 / 4 / 5 / 3V3, pins 1-8 top-to-bottom. Rotating the board on the same face so USB points up swaps the two columns; the order within each column is unchanged (8 pins)

No.	Name	Type	GPIO	Function
1	EN	C		Reset (CH_EN)
2	3	I/O	3	GPIO3; ADC1_CH3
3	2	I/O	2	GPIO2; ADC1_CH2; strapping input
4	1	I/O	1	GPIO1; ADC1
5	0	I/O	0	GPIO0; ADC1_CH0
6	4	I/O	4	GPIO4; ADC1
7	5	I/O	5	GPIO5; ADC2
8	3V3	P		3.3 V output

Right edge column in the official pin image view (USB pointing down): TX / RX / 10 / 8 / 7 / 6 / GND / VBUS, pins 1-8 top-to-bottom. Rotating the board on the same face so USB points up swaps the two columns; the order within each column is unchanged (8 pins)

No.	Name	Type	GPIO	Function
1	TX	O	21	GPIO21; U0TXD (chip UART0 TX)
2	RX	I	20	GPIO20; U0RXD (chip UART0 RX)
3	10	I/O	10	GPIO10; ADC1
4	8	I/O	8	GPIO8; ADC2 / strapping input
5	7	I/O	7	GPIO7; ADC1
6	6	I/O	6	GPIO6; ADC1
7	GND	G		Ground
8	VBUS	P		USB 5 V

The C3 mini is LOLIN/WEMOS's small ESP32-C3 board: ESP32-C3FH4 (RISC-V single core, 160 MHz, 4 MB flash inside the chip package — no external flash module), 12 I/O pins, one addressable WS2812B RGB LED, a USB Type-C port and 3.3 V logic, all on a 34.3 x 25.4 mm footprint that is compatible with LOLIN D1 mini shields. It ships with MicroPython and also runs Arduino, CircuitPython and ESP-IDF.

Both edge-pad columns are mapped from the official pinout diagram, using the board's bare-number silkscreen (this board carries no A0-A5 labels): the left column runs EN / 3 / 2 / 1 / 0 / 4 / 5 / 3V3 top-to-bottom (the number pads 0-5 are the ADC-capable GPIO0-5) and the right column TX / RX / 10 / 8 / 7 / 6 / GND / VBUS (TX/RX are the datasheet's default GPIO21/GPIO20) — exactly the 12 digital I/O the spec table claims. How it trades against the Seeed XIAO ESP32C3 is laid out in C3 mini vs XIAO ESP32C3. Board controls, from the v2.1.0 board image and tutorial: a RST button bottom-left and Button 9 (BOOT, GPIO9); download mode is hold Button 9, press Reset, release Button 9 — the native-USB flow, with no USB-UART bridge documented. No power slide switch on the board front. The WS2812's drive pin is not stated on the page and stays unrecorded.

Search hygiene matters here: plenty of results for "C3 mini" belong to the unrelated, differently-branded "C3 SuperMini" boards that reuse the term. This record is only the LOLIN/WEMOS product, current schematic V2.1.0 (V1.0.0 is the previous revision, kept as a scoped revision entry). The schematic PDF's text is vector-outlined, so the pin order above follows the page's official pinout diagram instead. This page renders the MCUID data record.