by Ali Slim

All-in-one USB to isolated-UARTx2/CAN/USB/RS485/RS232 converter

View all updates Jan 11, 2021

Dual Firmware How-to & Schematics Release

by A. Slim

Ollie is designed to be a flexible tool; one really cool feature is running a dual CAN firmware so the user can run the desired firmware without having to reflash the device every time.

Dual Firmware: How to Build and Stitch

The firmware can be selected using the DIP switch. The default firmware is forked from candleLight_fw and cantact-fw. Both firmware binaries are stitched together into one binary file. The base firmware is candleLight, on startup if the switch is toggled it will jump to CANtact/CANable. For more info on how to use the CAN supported applications see the github documentation.

If you would like to make any changes to the firmware and rebuild, here’s how:

  1. Download and install STM32CubeIDE

  2. Clone candleLight_fw and cantact-fw to your machine, and import then build.

  3. The build should result in 2 binary files, gsusb_ollie.bin and canable-xxxxxxx-dirty.bin

  4. Open gsusb_ollie.bin, using HxD

  5. Scroll down to the end of the file, and fill in FF until address 00003CFF.

  1. Again using HxD open canable-xxxxxxx-dirty.bin, press CTRL+A to select all and Copy.

  2. Go back to gsusb_ollie.bin and paste.

  3. canable-xxxxxxx-dirty.bin should start at address 00003D00

  1. Now save the new binary file. And to flash the new firmware follow the instructions on Github.

Here you go, this is how to combines both binaries into one. There are other methods for doing this, but I think this is the simplest way.

Schematics and Design Released

The main goal during design was to keep this device as compact as possible. The solution was to isolate the host USB, instead of isolating 15 pin channels. This helped maintaining a small footprint while keeping the cost relatively down.

The schematic files are now available on Github.

About the Author

A. Slim

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Product Choices



One Ollie interface module board, with custom enclosure.



One DB9 pluggable connector, for use with Ollie.


Ali Slim

Ali makes hardware tools.

A. Slim


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