There are already many USB-to-TLL debug boards on the market, but Olimex USB-SERIAL-L open-source hardware USB-to-serial board is more advanced than most with not only Tx/Rx pins, but also CTS/RTS pins, support for up to 3 Mbps speeds, and an adjustable voltage from 0.65V to 5.5V to cater to a wide range of boards.
Olimex USB-SERIAL-L specifications:
- USB-to-serial chip – Silicon Labs CP2102N
- Seven signal lines – +5V, GND, CTS, RTS, TX, RX, Vref
- Baud rate from 50bps up to 3Mbps
- Output buffers with adjustable levels from 0.65 up to 5.5V
- USB – USB Type-C port for power and connect to host
- Misc – Power, Tx, and Rx status LEDs
- Power Supply
- Input – 5V via USB-C port
- Output – +5V to the target
- Dimensions – 35 x 35 x 8 mm (Custom 3D printed plastic box)
- Seven 200 mm long cables
The Vref signal is used to adjust the voltage. It needs to be connected to the target’s VCC signal, if not connected, the voltage level will default to 3V. I’ve never needed to use CTS/RTS pins on a USB-to-serial board myself, but Olimex says those pins are used for some bootloaders to enter and exit automatically.
The CP2102N chip is well supported with drivers available for Windows, Linux, Android, and MacOS. Most OS will already come with drivers; if missing, they can be downloaded from Silicon Labs’ website. As with most/all Olimex designs, the USB-SERIAL-L is open-source hardware and you’ll find the KiCAD and PDF schematics and hardware design files, 3D files for the enclosure, and documentation on GitHub.
Olimex USB-SERIAL-L debug board can be purchased on the company’s online store for 9.95 Euros.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
Support CNX Software! Donate via cryptocurrencies, become a Patron on Patreon, or purchase goods on Amazon or Aliexpress
I have to say: I really love all the Olimex stuff. It’s usually original and affordable.
And OSHW. I’m learning a lot with their designs.
So, thank you and keep on the good work, Olimex team, if you ever come to this page.
^ This