NoVRAM HePAX questions (for you guys who have them already)


Mine is on the way.

1) If I copy user programs into the Hepax ram portion of the NoVRAM module, do I need to always have the HePAX pages still "burned" to access the programs in the ram? I assume so, but had wondered if they might be "reburned" with other ROMS once you had the 16K of ram full.

Does the HePAX rom provide OS extensions to run the programs once they are there? The manual for the HEPAX rom just says to execute them and it will find them in the ram. Does that mean that the ROM must be there for that to happen?

2) What ROMS have you guys put in the 8K rom space? I'm thinking the Sandbox rom, but ... ?



1. I don't think there's need to have the HEPAX pages loaded to run the FOCAL programs loaded on the NoVRAM. Of course you'll need them there to *load* the programs in the first place, but once there, they should behave like any other ROM page.

You will need the HEPAX pages present if what you upload there are data or ascii files, but that of course is another story.

2. I, of course, use the extra 8k for the SandBox_3D. Other alternatives I'd recommend are the modified_CCD (Array-less), but it's all a personal choice of course.



It looks really, really nice. :-) Can't wait to play with it.

And, High Rollers is one of my all-time favorite HP41 games.

Be great to see how fast it is in mcode.



Hi Gene, Angel

Certainly NoVRAM RAM pages can be used in a ROM-like fashion without the presence of HEPAX code.

NoVRAM-H.EXE does not allow you to build such configuration though. Anyhow, I've made an *experimental* config utility to use the upper four pages (#C to #F) as ROM while preserving the contents of RAM in pages #8 to #B.

I'll gladly mail you the required files (please take into account they're *experimental*) for you to play with (... enjoy High Rollers ;-) and (hopefully) show some NoVRAM features at HHC 2004.

Currently I'm using this config utility, NoVRAM-F.EXE ("F" stands for Free-config), to prepare some other RAM-Boxes code implementation into NoVRAM, as well as developing my new 2005 project's "page manager".

As a preliminary advance, said '05 project will handle 48K ROM and 64K RAM into a single module. Obviously it requires an efficient method to switch pages on and off at user's will (this is the difficult part :-)

On the HardWare side, the needed new PIC processor samples are not available yet (will probably be by end '04), so I'm testing with a bread-board *reduced* version with 24K ROM + 32K RAM in the meanwhile.

More to come as I finish my holidays... time to rest ;-))

Best wishes.


NOTE: RAM pages are still writable, provided you load any ROM image that's able to send the WRITE command (H'040) like David assembler for example.

Edited: 16 Sept 2004, 7:48 p.m.


So I stand corrected! This is obviously another difference between the original Hepax (remember that?) and the NoVRAM. Thanks Diego for the carification.



Angel, how much trouble is involved in potentially moving some functions between one ROM page and another?

I've been looking over the ROM manual and the MATH rom page also has the hacker subsection on it.

I've been much trouble is it/would it be to move the hacker lab piece over to the other rom page and drop in some of the very useful alpha and programming features from the Sandbox3d rom page?

For example, the functions: CALLXM, CFX, SFX, CSST, FC?S, FS?S, RCLF, REPLX, SFX, SKIPN, STOF, TOGF, and then the alpha functions such as AINT, AREV, MID$, LEFT$, RIGHT$, VIEWA and XTOAL would be wonderful USER-level programming features to have. That's 18 functions.

The HackerLAB contains 20 functions, many/most of which aren't directly for user-level programming.

What kinda work would be involved in doing that sort of shuffle? It would leave a 4K rom with all the math functions, the programming functions and a good deal of the alpha functions with another 4K rom with more of the really heavy Mcode goodies in it.

That would mean users would put one of the 4K roms in the NoVRAM and have a 4K rom page free for the CCD/OS page or some other 4K rom.

My fear is that you'll reply "It would take months!" :-)

And, of course, I don't have any clue whether the functions are about the same size in bytes, so this might be a false hope to begin with.




Hi Gene,

Well, even if it won't take months, it wouldn't be as simple as reshuffling the source code on a spreadsheet. MCODE is particulary nasty in that it sometimes is address-dependent code, and squeezing words into ROM pages is more an art than a science. Another little issue are the FAT's, which in the SandBox are "cross-referrenced", meaning that to overcome the 64-function barrier, some functions are included in the FAT they don't belong to, so to speak. This is done to go around the 4k space limitation per page, in case you wonder. (one particuler page can have just a handle of very long code functions, and thus exhaust its FAT quite quickly).

At any rate, it would take the time that I don't have in my hand right now, otherwise I'd be more than glad to take it for a spin for you.

Have you looked at my modified CCD-ROM? It has many of the functions you mention anyway, so it may be a good compromise in the mean time.


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