Piers Rocks has returned with a new update, introducing the One ROM USB version of his retro ROM replacement project. This latest revision adds direct USB support, simplifying the process of erasing and flashing firmware in just seconds. Instead of relying on serial wire debugging, users can now connect through USB, making setup more accessible for those who simply want a replacement ROM for their system.
The One ROM USB design includes a micro USB connector, electrostatic protection diodes, and a 12 MHz oscillator for precise clock timing. These additions allow the STM32 microcontroller to meet USB’s strict tolerance requirements. Piers explains that while the serial wire debug model will continue to offer more advanced features, the USB version provides a faster and easier method for most users.
During the video, Piers demonstrates the programming process. By entering DFU mode, the device accepts new firmware through USB. After some troubleshooting with voltage leakage and firmware bugs, he resolves the issues and confirms proper ROM byte serving on a Commodore 64. His adjustments restore stability and prove that the USB revision is fully functional.
An interesting highlight of the video is how he walks through both hardware and firmware modifications. From schematic changes to corrected code, Piers shows the iterative process behind achieving a working design. Though micro USB is the current standard for this board, he hints at the possibility of exploring USB-C support in future revisions.
For viewers eager to try One ROM, Piers mentions that a small batch of boards is available for sale on his store and eBay. Supplies are limited, but further runs may follow depending on demand. This release marks another step forward in making retro system maintenance faster and more user-friendly.
