Olimex USB-SERIAL-L is a USB-to-serial debug board with CTS/RTS pins, up to 3Mbps baud rate, adjustable voltage from 0.65V to 5.5V

OLIMEX USB-Serial-L

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

USB-to-serial debug board with CTS/RTS signals

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.

Share this:

Support CNX Software! Donate via cryptocurrencies, become a Patron on Patreon, or purchase goods on Amazon or Aliexpress

ROCK 5 ITX RK3588 mini-ITX motherboard
Subscribe
Notify of
guest
The comment form collects your name, email and content to allow us keep track of the comments placed on the website. Please read and accept our website Terms and Privacy Policy to post a comment.
4 Comments
oldest
newest
Luc
Luc
3 days ago

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.

Upgrade pi-top [3]
Upgrade pi-top [3]
3 days ago

^ This

andelf
andelf
2 days ago

Didn’t many esp8266 flashers use CTS/RTS signals to enter boot-mode?
Very interesting with an automatically adjustable level shifter at 3Mbps

Stefan Brüns
Stefan Brüns
9 hours ago

Warning – Absolute Maximum Ratings: 4.2V

This is what the datasheet has to say about the SN74AXC2T45, which is used according to the schematics.

There is the pin-compatible SN74LXC2T45, which has a nominal rating of 1.1V to 5.5V (6.5V abs max).

Boardcon Rockchip RK3588S SBC with 8K, WiFI 6, 4G LTE, NVME SSD, HDMI 2.1...