HP-41 Advantage

Can anyone explain (or point to an explanation) how the
bank switching in the Advantage module is done? Presumably
there is a mechanism in the module that recognizes which
bank it should be returning and does the selection. I would
like to be able to emulate the module in a FLASH/RAM box
that I am designing. I know how to do regular modules and
X memory but can't find a reference to this functionality.
Thanks in advance.

Monte Dalrymple


There's some information on bank switching in the ZenROM and/or ZEPROM manuals.
Basically, there are 2 instructions that are NOPs to the Nut processor, but which the bank-switched ROM chip recognises and acts upon. They select the primary or secondary bank of the 4K ROM they're executed from. There's
also a conventiuon that there are short routines at the top end of each bank-switched 4K chip to select the primary or secondary bank of that chip and then return.
I can look up more details if you're interested.


Ahh, that was the clue I needed. No mention of this in the Emery book, which is what threw me. Found it in the source code of Warren Furlow's emulator. For anyone interested, ENBANK1 is 100 hex, ENBANK2 is 180, ENBANK3 is 140 and ENBANK4 is 1C0. Now I'm off to the ROM images to see exactly how it's done. Thank you Tony.

Monte Dalrymple

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-41(CL): The easiest way to transfer FOCAL programs from a Linux PC to the HP-41 Geir Isene 13 3,545 12-05-2013, 02:40 AM
Last Post: Hans Brueggemann
  Advantage/CCD Matrix Challenge Ángel Martin 1 816 08-09-2013, 06:22 PM
Last Post: Thomas Klemm
  HP 41 Advantage module test RyanM 6 1,428 02-27-2013, 02:30 AM
Last Post: Angel Martin
  CCD and Advantage Pac Matrix Functions mark brethen 2 901 03-07-2012, 04:13 PM
Last Post: mbrethen
  What advantage does Wp34s have ove the HP50g? Bernard Rochlin 10 2,037 12-05-2011, 03:11 PM
Last Post: Walter B
  How to ? hp41 + advantage Patrice 0 503 07-20-2011, 01:55 AM
Last Post: Patrice
  Advantage Pac Curve Fitting mbrethen 9 1,817 06-26-2011, 08:06 PM
Last Post: mbrethen
  Did someone say that Advantage cannot be loaded in NoVRAM? Was it me? Diego Diaz 5 1,261 09-17-2008, 05:56 AM
Last Post: Diego Diaz
  Advantage Rom Module (Prototype version) Mike Brainard 10 1,884 02-26-2008, 03:54 AM
Last Post: Eric Smith
  Two versions of Advantage Pac? Karl Schneider 4 1,111 01-21-2007, 09:26 PM
Last Post: Palmer O. Hanson, Jr.

Forum Jump: