An ARM board that fits inside your USB connector

Feb 13, 2018

Project update 7 of 10

Tomu Campaign: Success

When we started the Tomu campaign, we were worried about the lack of good examples for the EFM32HG309 chip, but we believed that by providing everyone at LCA2018 a Tomu, combined with Tim’s previous efforts at publicizing the project, we would help to improve that situation. Boy, were we right! During the campaign the community has done some amazing stuff.

We now have an initial port of libopencm3, a cross-platform microcontroller library with drivers for a bunch of peripherals. This includes their "examples" repo, which contains a wide variety of USB demos like USB-Serial, USB HID for mouse and keyboard emulation example, USB Mass Storage Device, and even strange things like a USB MIDI example!

Also, the 1-Bit-Squared guys have made sure the popular BlackMagic debugging probe works with Tomu, and Piotr live streamed constructing an older version of the Tomu and helped us organize the tomu-harware releases page. We hope that Piotr will help us create some great instructional videos for building your own Tomu from scratch, for those so inclined.

Tim’s offer to send people who contribute to the project free Tomu boards still stands and he has already sent out over 50 during the campaign alone!

We have also made excellent progress on the stretch goals! As we mentioned in a previous update, the DFU bootloader is complete and we are working on improving the interface based on feedback from people at! We’re making bootloader updates more robust, and making storage more flexible. We’ll continue working hard on making the bootloader reliable and stable so that it can act as a failsafe when mistakes happen during programming. The bootloader is important and we want to get it right.

Additionally, we are working hard at getting the injection-molded cases. China has basically shut down for the spring festival holiday, and won’t start back up until the end of February. Once that happens, we can get to work cutting steel for the plastic molds, which usually takes a month or two. Once we have the molds, we can produce plastic cases, and once we have plastic cases we can produce Tomus, package them up together, and deliver them to you.

The other thing we’ve been working on is redesigning the board to work better with a case. As mentioned in a previous update, we’ve started work on the case design. To verify the fit is good, we need to produce some sample boards with the new PCB. Unfortunately, our normal PCB vendors had already closed up shop for the holidays, as had the backup vendors, and most third-party quick-turn PCB houses can’t do the 0.6 mm boards required by the plastics. We’d like to extend a big thank you to Hackvana, who was able to produce the prototypes in the correct thickness. We’ll update you when those arrive and we can do mechanical integration with a 3D-printed part, before sending the boards off to the plastics vendor for final measurement and mechanical testing.

Once again, thank you to everyone! We’re on-track to deliver boards by the deadline, and we’ll keep you updated as production proceeds. Thank you for helping us put a computer in every USB port!

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