An attempt to standarize HP-41 Bank Switching.

[Diego Diaz]

Hi all,

After some e-mail converasion held on May past year and including Ángel Martín, Monte Darymple, Sylvain Côté and myself about the latest Bank Switched ROMs developed by Ángel and the way they were handled both in the 41CL and Clonix/NoVs, it was clear that the single BS used in my modules doesn't cope with the needs of keeping track of the selected bank on every page/port.

At this point, the most appropriate BS method was the one implemented in the 41CL which invloved port dependent BS.

At first it looks like a simple modification to include page dependent BS in the NoV's module firmware, so I made the required changes and they went to the latest revision as of Oct. 16 2020.

Regrettably, this page dependent BS scheme proven to cause problems when dealing with the Advantage module and its Bank Switched upper page, as reported some weeks ago for a NoV-64d user.

After a long and fruitful phone call with Ángel last week, it seemed that the best compromise to handle both the "old style" 2 banks BS in the Advantage and the new 4 banks used in the most recent modules will be to keep page dependent BS on pages #0-#7 and change pages #8-#F to port dependent BS.

If I've understood it right, this is the way the 41CL is handling ist BS (Monte can correct me otherwise).

I've built new firmware including this feature for the NoV-64(d), both in the HEPAX-1D and 1H+LIBRARY4 versions and have done some preliminary tests. However the number of possible combinations of modules and/or peripherals is way too large for me to test them all.

So I'd appreciate your help in testing these changes with the configuration of your preference before updating the firmware archive or include this changes in the rest of the modules.

Please contact me by PM or mail and I'll send the relevant files.

Thanks a lot for your support and best wishes from the Canary Islands (AKA: Caronte's doorstep lately )

Diego.