HP-97 enhancements

[teenix]

You never know, but I don't think the registers are directly accessible from any serial bus.

The clock project simulated key presses by placing values onto the PIK chip key data input lines at the right time and through the calculators normal key processing routines the value which ends up in the C register, was displayed.

I think the only time data is available is when the C register is being read or written to RAM. To extract this would require careful examination of the ROM instruction flow.

cheers

Tony