SR-56C? Interesting idea.

[teenix]

(06-11-2022 01:05 AM)pauln Wrote:  Incidentally, before writing RCL-57, I didn't realize that the calculator is constantly updating the display even when the calculator is idle. I guess that for anybody into hardware this must be obvious but it was a big surprise for me.

I imagine the display is multiplexed similar to the HP LED models, so if the display is not constantly updated it would go blank, unless in the case of a fault, a single segment may be on very brightly and possibly damaging. Also the keyboard is scanned during the display updating, so the processor can know when a key is pressed. More modern machines with low power LCD displays probably have processor interrupts to detect key presses and wake a processor from sleep mode.

cheers

Tony