HP48GX RAM card design

[Jonathan Busby]

(01-20-2021 09:18 PM)pdo Wrote:  

(01-20-2021 03:48 AM)wan Wrote:  About the bank switching card, I have some questions.
1 Can the high-level signal of the switches be connected to vccon instead of vcc, for power saving?
2 Can write protect switch be connected to the we line instead of the cdet line, for hardware level protection?

Hmm, interesting questions, but I can't answer them with any certainty because I don't know in detail how the processor chip works.

Perhaps there is some design documentation from HP somewhere that would enlighten us in this area, but unfortunately I'm not aware of any.

Paul

Well, I have the Seiko-Epson official catalog of SRAM cards ( and other memory cards ) with all the technical specs, but, unfortunately, I've moved to Colorado from Texas and most of my possessions are in storage ATM. I scanned the catalog and I have it saved on an external HDD but it is in storage as well. I also wrote down, a long time ago, all the salient information regarding HP48GX compatible memory cards, but, it again is in storage :/

Regards,

Jonathan