NoV-64D and HEPAX Questions

[Sylvain Cote]

Hello Mike,

I have read your last post and I understand what you want to do.
This is a very advanced configuration and the HP-41 was not designed to do this.
There are several constraints in your setup, some I can go around and some not.

For example, because your Extended-IO ROM is part of your double-X-Memory module shell, it cannot be deactivated and because HEPAX RAM from NoV module always use page 8 to 11, it mean that your triple module can only be inserted into either port 3 or port 4.

Also, you will need to verify which page the Ext-IO ROM uses, normally the Ext-IO use the lower page but in your case you have to validate it. I normally use HEPAX HEXEDIT or ZENROM MCED, go to the first address of a page where the XROM value is located, if it contains 000 then there no ROM there and if it contains or something else then I validate the XROM value with the one I am expecting. (Ext-IO XROM is 23 dec or 17 hex)

Code:

Port 3 lower page is page 12 → C000
Port 3 upper page is page 13 → D000
Port 4 lower page is page 14 → E000
Port 4 upper page is page 15 → F000

This knowledge is needed in order to configure the NoV Flash space correctly.

Another issue is that NoV HEPAX implementation always allocate 16K no matter what.
As a work around we can remove two pages from the HEPAX RAM link lists (page 10 and 11) and load ROM images in them, but in order to do so, the easier way would be use PIL-Box and a virtual cassette drive who would contains a virtual cassette that you will create that would contains the needed ROM images.

This is only the beginning and it will get more complicated as we go along.

The best platform to do these kind of advanced configuration is the 41CL or the DM41X.
I can probably do it with the upcoming MAXX module from Monte but the PILBox will be mandatory.
From what I know, I could also probably do it with the upcoming module from Meindert/Andrew/Thomas/... but until I build a prototype or have the real module, I do not know.
In all cases, you need to have a deep understanding of how the 41C page system and bank switching works.

Because I know my way around and I have all the equipment, I can create a configuration that does what you want or pretty close.
The setup will be complicated and lengthy, I will try to automate the personality switch but it may not succeed and in that case it the switching may be somewhat complicated.

Are you ready for this ?
Did you order Diego USB programmer for the NoV module ?
What version of HP-41 do you have ? (C, CV, CX)? (fullnut, halfnut)?
Do you have a HP-IL module ?
Do you have a PILBox ?