HP41C with Rp Pico attached

[MeindertKuipers]

(07-13-2023 07:16 AM)ThomasF Wrote:  During development I had some problems with some display-commands that added garbage to the display, until I realized that some constants (ie from a "LDI CON" instruction) were treated as commands instead of data.

Good progress! I am a bit behing with this development, but can sucessfully trace the bus in realtime now. Still working on the PIO design.
To distinguish between command and data you should keep track of the SYNC status during the instruction. If it is high it is the (first word of the) instruction, when low it is data or the second word of an instruction. Your disassembler is impressive!