Tech: HP35 anode driver

[teenix]

Hi all,

I was poking around in an old HP Journal looking at the HP35 block diagram and noticed that the cathode driver has a reset line, but not the anode driver. On looking at what limited detail I could find on the web, it looks like it doesn't have any reset.

The display digits are decoded by this chip depending on its internal timing around T1 - T4, but I can't find any way that these could be synchronised with the calculator timing. For example, a digit might appear at the anode driver in the middle of T3 for example and be decoded wrongly.

Just curious, anyone know more details?

cheers

Tony