The microUSB Programming Adaptor uUSB-PA5-II is a USB to Serial-TTL UART bridge converter which is simple, cost effective, very small and easy to use.

It uses a mini-B type USB connector to connect to your PC. The uUSB-PA5-II is based on the SiLabs CP2104 USB to UART Bridge IC from Silicon Labs. The predecessor of the uUSB-PA5-II was the uUSB-PA5, this featured a FTDI FT232RQ USB to UART Bridge IC, however this is no longer produced by 4D Systems. Both models are still however featured in the Datasheet.

It provides the user with multi baud rate serial data up to 3M baud rate, and access to additional signals such as flow control in a convenient 10 pin 2.54mm (0.1″) pitch Dual-In-Line package.

The main 5 pin interface is a standard 2.54mm (0.1″) pitch female header, designed to connect directly to a majority of the 4D Systems modules.

The uUSB-PA5-II is ideal for prototype or production.

RX and TX signals are both 3.3V and 5V tolerant.

NOTE: The uUSB-PA5-II requires a standard USB mini cable which is not included.

NOTE: Illustrations present the uUSB-PA5 instead of the uUSB-PA5-II, however only the uUSB-PA5-II is now available.

Information about the adaptor

  • USB 2.0 compliant Full Speed 12Mbps maximum speed, Suspend supported.
  • Hardware or Xon/Xoff handshaking supported, 300bps to 3Mbps (uUSB-PA5), 300bps to 2Mbps (uUSB-PA5-II).
  • UART supports 7 or 8 data bits, 1-2 Stop bits, odd/even/mark/space and no parity (uUSB-PA5)
  • UART supports 5, 6, 7, or 8 data bits, 1, 1.5 or 2 stop bits, odd/even/mark/space and no parity (uUSB-PA5-II)
  • Power on reset circuit
  • Virtual COM port drivers allow operation with existing COM port PC applications
  • Supports Windows 2000 and above, MAC (OSX-8 and above) and Linux (2.4 kernel and above)
  • USB powered
  • -40 to +85 degrees Celsius temp range
  • Small size, 33.7mm x 17.3mm
  • Traffic/Operation LED indicates board status
  • Additional flow control and features available for the user to solder, using standard 2.54mm (0.1″) pitch through holes along each side of the PCB.
  • RoHS Compliant

How to determine which COM port is allocated to the uUSB-PA5-II:

  • Go to Control panel and double click on the “System” Icon and the “System Properties” window will open up.
  • Click on the “Hardware” window tab and then the “Device Manager” button.
  • Go down the list and expand the “Ports (COM & LPT)” devices.
  • There you will see the COM port that has been allocated for the μUSB-PA5/PA5-II.
  • Take note of the COM port number (e.g. COM4) as you will need this when configuring the COM port for applications that need to communicate with the uUSB-PA5-II such as the 4D-Workshop IDE.

This product comes with:

  • uUSB-PA5-II Programming Adaptor


Operating Ambient Temperature

-40°C to +85°C

Storage Temperature

-40°C to +85°C

Module Dimensions (mm)

33.70 x 17.30 x 4.10



Country of origin


CCCN / tarif code


ECCN export control code






Package Dimensions L x W x H (mm)

70 x 50 x 30

Product Weight (g)


Weight with Packaging (g)




CE Mark



Viewing Area: N/A

Module Width: 33.70 mm

Module Height: 17.30 mm

Module Depth:4.10 mm

Module Weight: 15 g