HP97 The journey begins

[teenix]

Hi all,

The HP-55 CPU is nearing completion.

Here is an image of it running under the PIC clock generator. I haven't tested the frequency yet but it should be very close to 784KHz. I had to order some different value caps to change the PIC crystal loading and haven't fitted them yet, so will test then. You can see in the image that the original crystal is missing and a thin wire running up the right side of the calculator to the anode driver input.

The oscillator output can be switched on or off depending on whether the original crystal is working or not.

The calculator functions ok. The PC interface is working over Bluetooth and I can transfer programs back and forth as well as set functions. The [f][BST] key combination is working allowing a quick program clear function.

As with the other CPU boards, you can dump the calculator memory directly into the emulator.

cheers

Tony