Disable Disc ROM

Bryce · 15:11, 24 August 12

No. If that doesn't work, then it's not going to work. The jumper was only meant for CPC+ (and possibly CPC6128 ASIC version)

Bryce.

SyX · 16:32, 24 August 12

Thanks Bryce, well at least my 6128 preasic doesn't let disable the amsdos rom so easy

I always though is one of the last 6128 before the cpc+, its serial number is 671-9403169. And i have checked the CRTC and GA emulation and everything works (bugs included) exactly as in a cpc+.

TFM · 16:42, 24 August 12

Quote from: arnoldemu on 09:35, 24 August 12
TFM/FS show us some pictures of your pcb please!!!!

Can't access hardware from here. But it's a regular CPC6128 PCB and a regular SF2 or RRB PCB. I try to care about it at X-mas, when I hopefully visit Germany for few days.

TFM · 16:47, 24 August 12

Quote from: SyX on 15:04, 24 August 12
I have checked in my 6128 preasic, disabling the internal cpc rom 7 with the MegaFlash jumper and i only get continuous resets. Do i need to do something else???

Yes, the MF ROM7 needs a valid content. But to start ROManager (basic version) you need MF ROM 7 switched off. Switch it on directly before you want to burn it.
Well, I assume you did it that way already

So, no, no additional ideas.
(Or try to clear the MF ROM 7)

SyX · 18:51, 24 August 12

Well, it was a fast test, but now i have made a few extra tests using the ROManager (rom version) and once is launched, i have disabled the internal rom 7 in the MegaFlash.

And strange things happen

, i have never touched the rom 7 in the MegaFlash, in theory had to be the ParaDOS that Bryce put there, but the ROManager detects the name as "KD" !?!?!?!

Have copied ParaDOS rom over position 7, but the rom always get corrupted (has a lot of M and m) and its name appears as "KD". I get crashes copying others roms (as maxam)... but the most incredible, i can copy perfectly the AMSDOS rom and nothing strange happens, not any byte is corrupted and works great... WTF?!?!?!?!

There is another thing that works great, i can park the rom in position 7 and then after reset, the rom in position 7 is disabled and the internal rom 7 is not enabled (the MF jumper is in off). And if i haven't another disc rom in other position (i usually have ParaDOS in position 6), then after a CAT or RUN" ... i get the "Press Play Then Anykey..."

That means, it works!!! The internal rom 7 is disabled in my machine when i change the jumper for rom 7 in the Megaflash...

... but now the question is why can i not put ParaDOS in ROM 7 in the MF???

TFM · 19:32, 24 August 12

Well, if you copy Amsdos to ROM 7 then the MF ROM 7 and the CPCs ROM 7 have the identical content, so it works.
If the MF ROM 7 contains something different, then this content gets IMO mixed with the internal ROM.

IanS · 19:37, 24 August 12

Quote from: SyX on 18:51, 24 August 12
Have copied ParaDOS rom over position 7, but the rom always get corrupted (has a lot of M and m) and its name appears as "KD". I get crashes copying others roms (as maxam)... but the most incredible, i can copy perfectly the AMSDOS rom and nothing strange happens, not any byte is corrupted and works great... WTF?!?!?!?!

Sounds like it's not disabling the internal rom at all. With different rom internal and external, both driving the data bus, you get random values "KD" etc. With the same content internal and external, the bus gets driven to the same value from two sources, so still works ok.

TFM · 19:47, 24 August 12

That's what I wrote

gerald · 19:51, 24 August 12

Well, looks like SyX tests shows that pre-asic does not allow disabling rom 7 either.

The Campusoft ROMBOX is from 1995, and support + range as well as the old range.
So 'earlier' means non plus range

SyX · 20:08, 24 August 12

Sure IanS, that is the logical explanation and the parking only works by luck, jejeje.

Gerald, i'm with you

IanS · 20:11, 24 August 12

Quote from: SyX on 20:08, 24 August 12
Sure IanS, that is the logical explanation and the parking only works by luck, jejeje.

As I understand it, the parking function just changes the first byte to FF. As long as combined data from internal rom (01) and external rom (FF) doesn't cause the byte read to be a zero or 1, the rom will be effectively parked.

TFM · 20:13, 24 August 12

No. Park inverts the first byte. Else unpark would not be possible.

arnoldemu · 11:29, 27 August 12

Quote from: gerald on 19:51, 24 August 12
Well, looks like SyX tests shows that pre-asic does not allow disabling rom 7 either.

The Campusoft ROMBOX is from 1995, and support + range as well as the old range.
So 'earlier' means non plus range

The plus documentation specifically says it is now possible to disable rom 7.
I was hoping the pre-asic would allow it too, but no syx has proved this

News:

Disable Disc ROM