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General Category => Amstrad CPC hardware => Topic started by: llopis on 17:12, 13 April 20

Title: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: llopis on 17:12, 13 April 20

Based on @gerald (https://www.cpcwiki.eu/forum/index.php?action=profile;u=250) 's idea and @Bryce (https://www.cpcwiki.eu/forum/index.php?action=profile;u=225) 's implementation, I finally got around to making the hardwired socket to replace the HAL and force the 2nd RAM bank as the default. It came in super handy already!


https://youtu.be/LLVHJO-aj3Q
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: XeNoMoRPH on 20:13, 13 April 20
you have golden hands  :o :o
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: llopis on 23:31, 14 April 20
By the way, check out the PCB that David Anders is making for this. With jumpers and all to switch between bank 1 and bank 2!
https://hackaday.io/project/170949-amstrad-cpc-6128-halmem-tester (https://hackaday.io/project/170949-amstrad-cpc-6128-halmem-tester)
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: TotO on 23:34, 14 April 20
Always funny to see peoples putting "copyrights" for the posterity over things took from forum.
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: zhulien on 08:07, 15 April 20
Although not hardware, you can use the OUT command from BASIC to swap entirely to the 2nd 64K bank.  It has a neat use in itself.  When you do that, the CPC is still running, but you can't see anything - you can hear the DEL key still beep.  But... if you run a copy protected game, it usually loads then crashes - if it doesn't crash, you can press a reset button - and... the 2nd 64K remains in tact surviving the reset, decoded and ready to save as a cracked game.
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: pelrun on 08:31, 15 April 20
Always funny to see peoples putting "copyrights" for the posterity over things took from forum.
Explicitly declaring copyright and an open license is the best approach here if people want to safely use his files.

It's not even a technicality - the board layout absolutely is his copyrighted work, even if the schematic is public domain or trivial. That's the way the laws work. Open Source *relies* on copyright, as the only safe way to provide free access to IP is through that lens. Public Domain simply does not exist as an accessible legal option, unless the source predates the birth of the Mouse (thanks Disney! pbbbt)
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: TotO on 09:08, 15 April 20
Totally useless...  :laugh:  (Copyright this smiley with your name too)
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: gerald on 09:36, 15 April 20
Always funny to see peoples putting "copyrights" for the posterity over things took from forum.
Look, it did not took things from the forum, it took it from a video on youtube  ;D
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: TotO on 10:07, 15 April 20
Look, it did not took things from the forum, it took it from a video on youtube  ;D
So, it is OK !  ;D
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: Bryce on 10:23, 15 April 20
What's the point of the PCB, other than it looking a bit neater? You only use it while debugging the board, so it's a lot of soldering and having a PCB made for nothing.

Bryce.
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: llopis on 11:05, 15 April 20
What's the point of the PCB, other than it looking a bit neater? You only use it while debugging the board, so it's a lot of soldering and having a PCB made for nothing.
It's neater for sure. And it comes with a built-in label :-)


But the main reason for it I think are the two jumpers: That way you have an easy way to switch between bank 1 and bank 2.


Anyway, just a fun toy.
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: Bryce on 11:45, 15 April 20
But the two jumpers are useless too. It makes the test more complicated. With the simple wire solution: Test lower RAM - Ok, or not? Take out HAL and replace with wired socket - Test upper RAM, ok or not? Once that's done, there no reason why you would want to switch back and forth any further. With the PCB, you take the HAL out and then re-insert it into the PCB?? Just to test it in the configuration it already had before you touched it??

Makes absolutely no sense to me.


Bryce.
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: gerald on 17:48, 15 April 20
But the two jumpers are useless too. It makes the test more complicated. With the simple wire solution: Test lower RAM - Ok, or not? Take out HAL and replace with wired socket - Test upper RAM, ok or not? Once that's done, there no reason why you would want to switch back and forth any further. With the PCB, you take the HAL out and then re-insert it into the PCB?? Just to test it in the configuration it already had before you touched it??

Makes absolutely no sense to me.


Bryce.
Well, the bank 0 configuration allow you to check that bank 0 is faultly because of RAM and not the PAL.
But it is still cheaper to make 2 adapters out of a socket than making a PCB .....
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: gerald on 23:04, 15 April 20
Based on @gerald (https://www.cpcwiki.eu/forum/index.php?action=profile;u=250) 's idea and @Bryce (https://www.cpcwiki.eu/forum/index.php?action=profile;u=225) 's implementation, I finally got around to making the hardwired socket to replace the HAL and force the 2nd RAM bank as the default. It came in super handy already!


https://youtu.be/LLVHJO-aj3Q (https://youtu.be/LLVHJO-aj3Q)
BTW, for the second bank(s) check, you can have a go on the WIP version : https://www.cpcwiki.eu/forum/hardware-related/another-faulty-6128-is-it-ram/msg180951/#msg180951
It will not tell you which IC to look at, but will check up to 4MB.
Title: Re: Video: Forcing 2nd RAM Bank on the Amstrad CPC 6128
Post by: zhulien on 08:56, 25 June 21
I wonder if a variant of this could be made to let you switch only which bank the video displays from?  'that' could be useful.