Progress!

The PCBs are soldered up (minus the switches, but they do work) and the PiDP-10 started to do its first blinkies. Admittedly, it still thinks it is a PDP-8 with a novel panel layout (I used modified pidp8i software for testing), but blinkies nevertheless.

As it turns out, the new-to-me MCP23017 GPIO chip is really easy to control. Just a few lines of code; and the speed of the I2C bus is OK for this application. That was one concern: 24 bits of I/O a few hundred times per second, with enough time in-between to light up the LEDs in the multiplexing routine. I had to up the I2C clock on the Pi, but that was easy too. Everything is easy with a Raspberry Pi. Sometimes.

Hopefully, the switch panel cover gets through Customs soon. Then, I have a complete demo machine :)

Now on to modifying Richard Cornwell's KA10 simulator, so the machine can start to feel its 36 bits of simulated power! Oh, and soldering 72 switches. A chore I'd better get used to.