Author Topic: Open Source, DIY 512KB RAM Expansion  (Read 24563 times)

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Offline revaldinho

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #125 on: 23:30, 25 January 21 »
Ps. Do you know what the correct DIP switch settings on the memory card will be for my setup?



See quick reference card attached.


All the other documentation is on the project wiki.




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Offline Animalgril987

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #126 on: 18:39, 30 January 21 »
I'm afraid that my ram card appears to be dead. Toto's ram test shows 0k CPU ram.
I gave the CPC edge connector a good clean and used a multimeter to check continuity from the CPC traces to the through connector on the backplane ( all lines were good).
So I connected everything up, and it doesn't look like it's working.

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Offline Skunkfish

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #127 on: 00:39, 31 January 21 »
Hi Alan, I'm sorry to hear that!

Is the switch on the backplane card set to CPC or PSU? This should be CPC if there's no PSU connected to the card directly.

Also, have you tried connecting the card directly to the cable rather than via the backplane card? Is the result any different?
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Offline Animalgril987

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #128 on: 15:36, 31 January 21 »
I'll try giving the CPC edge another clean. If that doesn't work, I'll try directly connecting the card to cable.
I've tried switch set to CPC and using an external psu ( with switch set to psu).


Alan
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Offline TotO

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #129 on: 15:51, 31 January 21 »
I'm afraid that my ram card appears to be dead. Toto's ram test shows 0k CPU ram.
Please, contact me by email to see how I can solve your problem. :)
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Offline revaldinho

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #130 on: 17:20, 31 January 21 »
I'm afraid that my ram card appears to be dead. Toto's ram test shows 0k CPU ram.

If the RAM test shows 0K CPU RAM, is there a possibility that you made an error in typing the program in ?

[EDIT - removed incorrect results for a '464' which would return 0K. Yes, the unexpanded 464 would indeed return CPU RAM: 0K ]

One thing I would check on the board, since you mentioned you had a multimeter, would be the supply voltage. Take a reading from the RAM pins - bottom left is ground, top right should be +5V.

Beyond that, if it is a hardware failure then the vendor (@skunkfish) should have the opportunity to put things right for you.


« Last Edit: 17:47, 31 January 21 by revaldinho »
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Offline Animalgril987

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #131 on: 17:35, 31 January 21 »
Thanks everyone for all suggestions. Yes it would appear to have still been some grime on one of the edge contacts.


All is good! Toto's ram test shows 448k CPU ram ( 464 in full C3 shadow) with both CPC power and external psu.


Alan


 ;D ;D
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Offline revaldinho

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Re: Open Source, DIY 512KB RAM Expansion
« Reply #132 on: 17:45, 31 January 21 »
That's great! You should get the full 512K RAM in DK'tronics mode and for most software that will be fine. FutureOS is on of the very few programs which needs the shadow mode.


(BTW, Sorry I was wrong with the CPU RAM report - I tried that program on a a 6128 and of course it did report CPU RAM 64K since it has the extra bank built-in.  :picard: On a stock 464 it would return 0K. Unfortunately my DDI-3 isn't working with my own '464 to load the program on that at the moment. May well be more edge connector problems...)

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