I just got back my 7 segment LED circuit boards from Pad2Pad, and hooked one up, and connected it to my HC08 for testing. The way this works is that the processor only needs to drive 4 lines: data, shift, load into display and reset. My test software program runs a 16-bit counter (of which we only see 12 bits), displaying the bottom three digits as hex as it counts upwards.

And here are the results:

Flawless! The circuit worked without any problems or needing any line cuts or jumpers. Hopefully I’ll have a chance to wire up three of these and hook it up to my calculator software soon…