4 layers91 × 53.1 mm
Nff pcb
o7-machinehum/flipper-blackhat
Linux based WiFi pentesting device for the Flipper Zero.
184 parts300
2 layers18 × 33 mm
Usb to uart
solderdemon/usb-to-uartA compact USB-C to 5V UART adapter based on the WCH CH340C.
- Size
- 18 × 33 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 12
- Nets
- 14
- Pads
- 62
- Tracks, vias
- 66, 26
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 8 Sep 2026
- Updated
- 8 Sep 2026
Overview
Usb to uart is an open-source printed circuit board by solderdemon, from the solderdemon/usb-to-uart repository on GitHub. It is a 2-layer board of 18 × 33 mm with 12 parts on 14 nets, routed with 66 tracks and 26 vias.
It is built around the CH340C. Its parts include 5 resistors, 3 diodes, 1 capacitor, 1 IC and 1 connector. It belongs with the interfaces and adapters boards of this library.
Main components
1README
README.mdUSB to UART Adapter (CH340C)
A compact USB-C to 5V UART adapter based on the WCH CH340C.
Designed primarily as a direct plug-in serial adapter for retrocomputing systems like the rosco_m68k and rosco_6502, but also works with any 5V microcontroller or serial device using a standard 6-pin header.
Highlights
- Controller: WCH CH340C (integrated clock oscillator — no external crystal required)
- USB Interface: USB Type-C receptacle with 5.1 kΩ CC pull-downs (compatible with both C-to-C and A-to-C cables)
- Logic Level: Native 5V TTL (powered directly from USB VBUS; ideal for 5V retro hardware without level shifters)
- Flow Control: Hardware RTS / CTS lines connected
- LED Indicators: PWR (power), TX (transmit data), RX (receive data)
- Header: 1×6 right-angle 2.54 mm (0.1") pin header
Pinout
The 6-pin header is labeled on the silkscreen from the perspective of the target board, matching the UART pinout on rosco_m68k and rosco_6502:
| Pin | Silk Label | Adapter Signal (CH340C) | Target Signal (rosco) | Description |
|---|---|---|---|---|
| 1 | GND | GND | GND | Ground (square pad) |
| 2 | RTS | CTS (pin 9, input) | RTS (output) | Flow control from target to PC |
| 3 | VCC | VBUS (5V output) | VCC (5V) | 5V power from USB |
| 4 | RX | TXD (pin 2, output) | RX (input) | Data from PC to target |
| 5 | TX | RXD (pin 3, input) | TX (output) | Data from target to PC |
| 6 | CTS | RTS (pin 14, output) | CTS (input) | Flow control from PC to target |
Note: Because the silkscreen matches the target's pinout, you can plug this adapter directly into a rosco_m68k or rosco_6502 serial header with a 1:1 connection without crossing TX/RX or flow control lines.
Board Views
| Top Side | Bottom Side |
|---|---|
 |  |
Bill of Materials (BOM)
| Reference | Value | Package / Footprint | Notes |
|---|---|---|---|
| U1 | CH340C | SOIC-16 | USB to serial bridge with internal oscillator |
| J1 | USB-C 14P | TYPE-C-31-M-12 | USB Type-C receptacle (USB 2.0) |
| INPUT | Conn_01x06 | PinHeader 1×06, 2.54 mm | Right-angle pin header |
| C1 | 100 nF | 0603 | VCC / V3 decoupling capacitor |
| R1, R2 | 5.1 kΩ | 0603 | USB-C CC1 / CC2 pull-down resistors |
| R3, R4, R5 | 1 kΩ | 0603 | Current-limiting resistors for LEDs |
| D1, D2, D3 | LED | 0603 | PWR, TX, and RX indicators |
Manufacturing & Hardware Files
- KiCad Project: main.kicad_pro, main.kicad_sch, main.kicad_pcb
- Schematic PDF: main_schematic.pdf
- Gerbers:
- Ready-to-order archive: usb_to_uart_production_gerber.zip
- Unpacked layers in gerber/ folder
- PCB Specs: 2-layer board, 1.6 mm thickness, standard 1 oz copper, 6/6 mil trace/space
License
Open Source Hardware (OSHW).
Parts
12| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 1k | R_0603_1608Metric | R3, R4, R5 |
| 2 | 5.1K | R_0603_1608Metric | R1, R2 |
| 1 | 100nF | C_0603_1608Metric | C1 |
| 1 | CH340C | SOIC-16_3.9x9.9mm_P1.27mm | U1 |
| 1 | PWR | LED_0603_1608Metric | D1 |
| 1 | RX | LED_0603_1608Metric | D3 |
| 1 | TX | LED_0603_1608Metric | D2 |
| 1 | UART_A | PinHeader_1x06_P2.54mm_Horizontal | INPUT |
| 1 | USB-C | USB_C_Receptacle_GCT_USB4105-xx-A_16P_TopMnt_Horizontal | J1 |
Similar boards
- 2 layers66.8 × 34 mm
- 2 layers13.7 × 21.4 mm
- 2 layers192.4 × 50 mm
- 2 layers84.2 × 52 mm
- 4 layers43 × 49 mm
- 2 layers36 × 58 mm
Ups adaptor
aronreid/ups-to-esp32
Put a USB-only UPS on the network: an ESP32-S3 board and firmware that serves NUT on TCP 3493, with a web UI. No host computer, no Raspberry Pi.
38 parts130GPL-3.0 - 2 layers85 × 56 mm
Questions
How big is the Usb to uart PCB?
It measures 18 × 33 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Usb to uart use?
12 parts, built around the CH340C. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Usb to uart KiCad files?
From the solderdemon/usb-to-uart repository on GitHub, at the commit this page was made from: the board is main.kicad_pcb and its schematic main.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Usb to uart design in my own project?
Its repository states no licence, so its author keeps all rights: ask solderdemon before reusing the design.