Hi all,
through my investigations into FlySpy and loading I found a need!
Would it be possible for a PCB to be designed that would be a plug in solution to allow switching between 2 FIrmware 3k roms or 2 16k DOS roms on the CPC.
Are the pin outs close enough for the same device to be used for both?
I would be happy to order, solder and make a small batch of these adaptors as I would need several myself but I am not tech savvy enough to design the board.
They would need to have 2 Eprom Sockets and switch headers (Maybe jumpers too if the pinout on 32k and 16k roms are not compatible) so that the Firmware could be switched from Basic1.0 and 1.1 on a CPC 464 and the DOS from AmsDOS to Parados on a CPC 6128 without needing to open the case.
If someone is willing to help we could make a really useful board.
I know it can be done with piggybacking the chips and adding a switch, but a little PCB is neater IMHO and is totally reversible.
Hopefully I am not insane here :)
Craig
Sure, il is not hard to do, but better to unsolder the previous one and add a socket. (or using an external board)
I should take a little time to design a board with 128K flash and a dipswitch to set 4x32K in example.
Quote from: TotO on 11:51, 08 August 19
Sure, il is not hard to do, but better to unsolder the previous one and add a socket. (or using an external board)
I should take a little time to design a board with 128K flash and a dipswitch to set 4x32K in example.
Hi Toto, the idea was obviously to socket the CPC board and then have a small plug in PCB with 2 sockets on it, a header for the switch to select which rom is used and a jumperblock (if required) to set the same device as suitable for 32k roms (Basic 1.0 -> 1.1) or 16k roms (AmsDOS -> Parados). This way the whole mod is kept internal in the CPC without anything on the expansion port.
this way only one PCB needs to be designed to be useful for switching the DOS (in a CPC6128 or DDI1) or the Firmware (in a CPC 464)
surely this will not need flash? Just a couple of sockets, some IC Pin Headers (to fit into the socket on the Amstrad board) lots of Know how ... That I don't have ;)
craig
Why using two IC when one is enough to store four FW/BASIC ROM combo? ;D
I think it is better to not split the firmware and its basic to avoid compatibility problems.
Sure, piggy back is a way to do if not hard to find the good socket for this usage.
In case anyone is wondering why I thought of this type of device.... well testing a FlySpyCDT this last few days has revealed that it is a pain in the arse game to load if you have any mods on your hardware at all....
If like me you have a 664 rom in a CPC 464 (to get Basic 1.1) the game won't load, even from tape, as no AmsDOS is present. Plug in an external AmsDOS (DDI-1 or DDI-4) and it's happy again
Or if like me you have a ParaDOS rom in your cpc6128, guess what the game won't load as it does not lile ParaDOS either.
therefore for this (and other incompatible games) it would be really handy to switch between the Firmware and DOS version without opening the case and swapping IC's around... or building a less reversible piggyback or DualOS type system with 32k and 64k eproms.
Kind Regards
Craig
Quote from: TotO on 14:29, 08 August 19
Why using two IC when one is enough to store four FW/BASIC ROM combo? ;D
I think it is better to not split the firmware and its basic to avoid compatibility problems.
Sure, piggy back is a way to do if not hard to find the good socket for this usage.
2 IC's because not everyone ones needs are the same. Some people might want say Basic 1.1 and FW3.16 and the Stock. Others may want ParaDOS 1.1 and ParaDOS 1.2, Or RoDOS or hell anything else that works in slot 7 ;)
All I need is a switch for the board to allow 2 roms to be switched.. No need to bother with messing around with further expansions... If I get a board that will do that I'll order the minimim amount of PCB's becuase I'll be using 4 myself.. the rest I can make up and sell on, or provide as kits or whatever... I'm happy to pay for the 4 I need, hell the rest I'll give away.. the component cost is minimal. A switch, 2 sockets (+1 for the PCB), pin header strips, some wire and jumpers
Or have I missed something?
Craig
ACU did a rom changer project back in the day.
It's not really possible to override the internal disc rom in the 6128 though, at least not reliably (and not without causing bus contention, don't do it kids!) but if you yank the internal ROM then you can supply both externally and switch between them.
We already have that:
- X-MEM
- LowerROM board
Yes... It will cost more, require more soldering and took more room to have 2x 32K ROM instead of 1x128K (4x32K split).
With this configuration you can have in example: FW1.0/BASIC1.0, FW2.0/BASIC1.1, FW3.0/BASIC1.2, FW3.x/BASIC1.2
So, no need to have a second switch to set the BASIC ROM and no risk to set the wrong FW/BASIC combo for beginners.
Quote from: pelrun on 14:39, 08 August 19
ACU did a rom changer project back in the day.
It's not really possible to override the internal disc rom in the 6128 though, at least not reliably (and not without causing bus contention, don't do it kids!) but if you yank the internal ROM then you can supply both externally and switch between them.
I don't buy that. I once did the DualOS mod on a CPC 6128 that put both AmsDOS and Parados on a 32k eprom and provided a switch to toggle them. Whilst I could do that again it involved more than I am hoping for. Is it really not possible to devise a small PCB that fits into the AMsdos socket an and provides 2 sitchable sockets that can be populated with option roms that can then be switched between?
Quote from: TotO on 14:47, 08 August 19
Yes... It will cost more, require more soldering and took more room to have 2x 32K ROM instead of 1x128K (4x32K split).
With this configuration you can have in example: FW1.0/BASIC1.0, FW2.0/BASIC1.1, FW3.0/BASIC1.2, FW3.x/BASIC1.2
So, no need to have a second switch to set the BASIC ROM and no risk to set the wrong FW/BASIC combo for beginners.
The board should switch directly between the 2 socket on it... One having the original IC removed from the AMstrac board to fit the socket and a second socket... in the case of a Basic upgrade this would be an AMstrad 40009 and an Eprom programmed with a CPC 664 Lower rom and Basic 1.1.
in the case fof the AMsDOS rom on the 6128, this would be a Amstrad 40015 and a Parados 1.2 eprom.
No splitting of images, no flash, nothing. just a PCB, 2 sockets, a switch etc...
Sorry, I thought you wanted to plug something into the expansion port to override the internal ROM, which isn't possible.
Replacing the internal rom itself whether physically or electrically is fine.
Quote from: pelrun on 14:39, 08 August 19
It's not really possible to override the internal disc rom in the 6128 though, at least not reliably (and not without causing bus contention, don't do it kids!) but if you yank the internal ROM then you can supply both externally and switch between them.
We discussed that several times, it's 100% reliable for some PCB versions, for others not. Depends what you have.
Only one of my five CPCs here can not use an external ROM 7. All Plus do anyway.
Aaaaannnd there it is.
It doesn't matter if it's occasionally reliable. It still depends on winning a bus contention battle, which is literally shorting outputs together and hoping the currents that occur when they drive different levels won't damage something. You can do that with your hardware if you want, I'm not having it on mine.
By the way, a "Amstrad Version of the Amiga Kickstart Switcher board" do not have to handle the ROM7.
If you want to add a AMSDOS/PARADOS switch, it has to be on the DDI-1 for 464/664 or instead of the AMSDOS ROM socket on 6128. (after removing the original IC and cut the apropriated wire if required)
Quote from: GUNHED on 16:05, 08 August 19
We discussed that several times, it's 100% reliable for some PCB versions, for others not. Depends what you have.
Only one of my five CPCs here can not use an external ROM 7. All Plus do anyway.
I am taking about a board that plugs into the AMSDOS socket INSIDE the CPC 6128.
This board has 2 sockets on it... One for AmsDOS and one for Parados. A switch from the board to the back of the case to swap between the 2.
Job Done.. No need to override anything from the expansion port and 100% compatibility with all CPC 6128's as well as the DDI-1
Basically a way of swapping the physical roms over without taking the case apart, pulling one IC out and putting the other back in. Is this so hard to understand?
Quote from: TotO on 18:08, 08 August 19
By the way, a "Amstrad Version of the Amiga Kickstart Switcher board" do not have to handle the ROM7.
If you want to add a AMSDOS/PARADOS switch, it has to be on the DDI-1 for 464/664 or instead of the AMSDOS ROM socket on 6128. (after removing the original IC and cut the apropriated wire if required)
See my reply to TFM.. I am not taling about ANYTHING On the expansion port.. this is ALL internal.. Plugging into the AmsDOS Rom spot on the CPC mainboard (once you put a socket in) or the 40009 socket on the CPC464 (to provide a switched upgrade to Basic 1.1)
Nothing on the expansion port at all... guaranteeing 100% compatibility as the chips are in the original places on the main PCB, Just a little switch to change them over to an upgraded version as required
Quote from: CraigsBar on 22:39, 08 August 19
I am taking about a board that plugs into the AMSDOS socket INSIDE the CPC 6128.
Yes. And I quoted Pelrun. :)
BTW: One of my CPC6128 has 4 MB RAM and 2,5 MB FlashROM. All internal. Posted about that before too. ;)
@CraigsBar (http://www.cpcwiki.eu/forum/index.php?action=profile;u=482)
Do you want to do this to One CPC464 or 2 CPCs 1) 464, and 2) 6128 ?
Ray
Quote from: Audronic on 00:45, 09 August 19
@CraigsBar (http://www.cpcwiki.eu/forum/index.php?action=profile;u=482)
Do you want to do this to One CPC464 or 2 CPCs 1) 464, and 2) 6128 ?
Ray
Ideally one board for both. Teh 27c128 and 27c256 seem to be almost pin compatible so if the differences could be solved with jumpers then it will save my costs (And excess boards) ;)
I need 4 in all - as I have 2 cpc 464 needing a 32k (27c256) switch and 2 CPC 6128 needing the 16 k (27c128) switch. so if the board can be shared that would be brilliant.
I am sure @Shaun M. Neary (http://www.cpcwiki.eu/forum/index.php?action=profile;u=728) might take one or two of the spares, the rest will go up for grabs to the first that want them!
Craig