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blackjetrock · 05-31-2023, 08:31 AM

(05-31-2023 08:01 AM)ThomasF Wrote: Hi Andrew!

Very interesting project indeed!

I assume this is connected between the CPU-board and the main PCB/Keyboard.
Would it be possible to connect the "analyzer" between the PCB/Keyboard and the I/O-module?

The connections are soldered on to the CPU IC. That allows connection to the key matrix and the ISA/DATA etc bus lines. As it's a bus then it could be attached wherever those signals exist. You could build this into a module, I'd have thought, the components are small enough, but then you'd not have access to the keyboard matrix signals.

Quote:I guess that the information from (and emulating) the keyboard will be lost, maybe also vital part of the display I/O?
The reason I'm asking is that it might be possible to use a flex-strip (see this link), without soldering something inside the HP41.

Yes, you could connect it with a flexi circuit.

Quote:Or even using only an old module connector just to analyze the inter-module communication.

I think if you did build it into a module then you'd get access to all module and processor traffic as it is one bus connecting the modules,ROM,RAM and processor.

Quote:Emulating modules is one achievement, but with USB connection a lot of other interesting possibilities might also be possible ...
I.e. maybe emulating the card reader or Wand to insert/save programs into the 41 from a PC

Yes, I've had a quick think about that. As the hardware for the wand and card reader is in the module or reader then it's tricky to get data inserted into the machine as you'd have to write your own ROM.
I have loaded programs by pressing keys. You take the text of a program, run it through a tool, reprogram the Pico and then you can select a menu option on the Pico interface and it presses the appropriate keys to load the program.
I'm going to have a look at emulating RAM as well as ROM so it should be possible to save and load all of the RAM contents that is emulated over the USB.

But, yes, lots of options.

Quote:Cheers,
Thomas