I’m happy to report that the JRC-1 boards arrived a few days ago, and exactly as I predicted I had a build up and running by Christmas. Here it is, in all of its black solder mask glory:
I guess the third time’s a charm, because this is my third full build, and the board booted up with no hardware issues. It’s currently running at 4 MHz; it should run faster but I have not tried yet.
The board is not perfect; there are a couple minor problems with the layout. The footprints for the DS1813s (the reset and NMI controllers) are reversed, and the footprints for the expansion slots don’t fit the slot connectors I have. Neither problem is critical and both have easy workarounds, so at this point I am considering this design final. All of the the hardware design files (KiCad project and CPLD Verilog project), as well as the latest firmware code, are in the JRC-1 GitHub repository.
With the board up and running I am turning my attention to the firmware. Currently I’m working on cleaning up the code so that I can start the major work. Next up is getting the SD card driver working, and then work on JR/OS. That’s where the real fun begins!