The UM232H is a USB-to-serial/FIFO development module in the FTDI product range which utilizes the FT232H USB Hi-Speed (480Mb/s) single-port bridge chip to handle the USB signaling and protocols. Official reference can be found here


You can configure debugging tool using debug_tool option in “platformio.ini” (Project Configuration File):

platform = ...
board = ...
debug_tool = um232h

If you would like to use this tool for firmware uploading, please change upload protocol:

platform = ...
board = ...
debug_tool = um232h
upload_protocol = um232h

More options:



macOS contains default FTDIUSBSerialDriver driver which conflicts with debug tools which are based on this chip. FTDI Chip company recommends removing this default driver from a system. Everything should work after system rebooting. See detailed instruction in official application note (Page 16, Section 4: Uninstalling FTDI Drivers on OS X) AN134: FTDI Drivers Installation guide for MAC OS X


Please install “udev” rules 99-platformio-udev.rules. If you already installed them before, please check that your rules are up-to-date or repeat steps.

Wiring Connections

Please read 4. UM232H Pin Out and Signal Descriptions section for details.

UM232H Pin Board JTAG Pin Description
GND GND Digital ground
AD0 TCK JTAG Return Test Clock
AD1 TDI Test Data In
AD2 TDO Test Data Out
AD3 TMS Test Mode State

You will also need to connect VIO to V3V and USB to 5V0 of UM232H to power the FTDI chip and board. See UM232H Datasheet


Name Description
GigaDevice GD32V The GigaDevice GD32V device is a 32-bit general-purpose microcontroller based on the RISC-V core with an impressive balance of processing power, reduced power consumption and peripheral set.


Name Description
Arduino Arduino Wiring-based Framework allows writing cross-platform software to control devices attached to a wide range of Arduino boards to create all kinds of creative coding, interactive objects, spaces or physical experiences
GigaDevice GD32V SDK GigaDevice GD32VF103 Firmware Library (SDK) is a firmware function package, including programs, data structures and macro definitions, all the performance features of peripherals of GD32VF103 devices are involved in the package



For more detailed board information please scroll tables below by horizontal.

Name Platform Debug MCU Frequency Flash RAM
GD32VF103V-EVAL GigaDevice GD32V External GD32VF103VBT6 108MHz 128KB 32KB
Sipeed Longan Nano GigaDevice GD32V External GD32VF103CBT6 108MHz 128KB 32KB
Sipeed Longan Nano Lite GigaDevice GD32V External GD32VF103C8T6 108MHz 64KB 20KB
Wio Lite RISC-V GigaDevice GD32V External GD32VF103CBT6 108MHz 128KB 32KB