1mb rom maprom possible ?

[countzero]

I managed to burn a 1mb rom for my A1200 with piru's exec 44 and boing ball updates thanks to these wonderful threads and software by doobrey.

http://www.amiga.org/forums/showthread.php?t=25665
http://www.amiga.org/forums/showthread.php?t=22929

Now my question is, when I enable the maprom feature on my 1230MKIV, system cannot find the extended rom, since probably only the first 512k is mapped.

can it be possible to map full 1mb to fast ram ?

[motorollin]

Yes I believe it is possible. According to Doobrey you need the exec from a CD32 ROM.

--
moto

[motorollin]

Sorry I have just re-read your post and it seems you are using BlizKick to kick a 1MB ROM. Is that correct?

--
moto

[countzero]

no I don't blizkick them I made the 1mb roms and burnt them on to chips. Doobrey has provided a 1mb patch which for all execs, now you don't have to use the cd32 exec. My roms work fine and everything seems ok. However, when I enable maprom feature on the blizzard (which copies the contents of the rom to fastram for quick access, this is completely done by the blizzard card) it only copies and maps the first 512K and rest is not found.

edit : I think I made a mistake opening the thread, I meant maprom instead of fastrom.

[Matt_H]

Is it possible the Blizzard maprom can only handle 512K?

[Piru]

Blizzard maprom only does 512KB, indeed.

[Damion]

Piru wrote:
Blizzard maprom only does 512KB, indeed.

Bummer. (I've been thinking along similar lines here.) So the only option would be Blizkick using the "extresbuf" feature, correct?

[countzero]

what are my chances of removing the 27c256 on the MKIV, reading the firmware, making necessary changes for 1mb maprom feature and burning it into a new rom ? (hmmm 0 ? 0.5% ?)

[Zac67]

I guess it doesn't use the MMU, does it? If not, the remapping is done in glue logic and there's probably nothing you can do...

[Piru]

@-D-

So the only option would be Blizkick using the "extresbuf" feature, correct?

Well, the extra romtags could be put to extresbuf, sure. Not directly as a 2nd ROM though (the modules need to be relocatable).

[Piru]

@countzero

what are my chances of removing the 27c256 on the MKIV, reading the firmware, making necessary changes for 1mb maprom feature and burning it into a new rom ? (hmmm 0 ? 0.5% ?)

The actual MAPROM feature is some HW magic that is triggered by the software. I doubt it's expandable without some rather complex hw modifications (more complex than reflashing the EPROM).

Anyhow, the MKIV ROM can be read quite easily (just save it to a file). It won't help much in this case, however.

[Doobrey]

countzero wrote:
can it be possible to map full 1mb to fast ram ?

The only thing I can think of is to modify an MMU based ROM mapper.
The sources for MuFastRom are available on aminet, shouldn't be too hard to make it remap the 2nd 512k too.
I'll stick it on the 'to do' list. :hammer:

Edit:
 Something to keep in mind, the 040,060 and mmu.library all remap the $e00000-$e7ffff space used for the 2nd 512k ROM to some other address.
So if you've got an 040 or 060, then it's impossible to use a 1MB ROM for now. (already done a cunning fix that fools the library into thinking it's running on a CD32 so it doesn't remap the ROM away)

Also, bad news for A3000 and A4000 users, it looks like Fat Gary doesn't support 1MB ROMs, it doesn't generate the ROMEN signal for the 2nd 512k  :-(

[alexh]

Doobrey wrote:
Also, bad news for A3000 and A4000 users, it looks like Fat Gary doesn't support 1MB ROMs, it doesn't generate the ROMEN signal for the 2nd 512k  :-(

Yeah, bummer about that.

The Gate-Array (Gary) chips were some of the few chips that were actually designed and made by "Systems Group" (rather than Semiconductor Group).

Dave Haynie was a member of Systems group and is still quite vocal, perhaps he will know a thing or two?