HP97 The journey begins

[teenix]

Hi all,

I guess maybe a woo hoo!! is in order.

Probably the first time in history a magnetic card was written/read in a HP 67 from a home made CPU board. For me, the original CRC chip does still have a few hidden secrets but I'm pretty sure I've got it right. Anyway, the data on the logic trace looks pretty good. The data block stored on the card is well within the card ends and looks similar to the "magnasee" images in the HP journals.

The card read/write is still controlled by the same method as the original calculator hardware, which is directly from the HP67 original microcode, so I'm hoping all the other functionality like expecting card #2, data cards, pause to reload etc all work.

Still a lot of testing to go, but encouraging.

I thought of a new user option too (if it works) which is that the new cpu can time the data as it passes the read/write head and report the actual bit time. That way, eccentric cam adjustments might be easier.

cheers

Tony