New A3000 4MB memory

Arc/RPCs, peripherals, RISCOS operating system & ARM kit eg GP2x, BeagleBoard

New RAM for you?

Poll ended at Mon Sep 24, 2018 8:05 am

Yes - Quality connectors please!
9
56%
Yes - Much cheapness connectors
1
6%
Maybe - at some point...
2
13%
Narp - I have 4MB already
4
25%
Narp - I have 2MB already and it is plenty
0
No votes
Narp - I have 1MB already and it is adequate
0
No votes
 
Total votes: 16

Cutter
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Re: New A3000 4MB memory

Post by Cutter » Fri Nov 09, 2018 6:07 pm

Let me know if you want another tester - happy to help.

cmorley
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Re: New A3000 4MB memory

Post by cmorley » Sat Nov 10, 2018 11:56 am

myelin wrote:
Fri Nov 09, 2018 6:00 pm
Is there any chance this could be caused by old decoupling capacitors on the MEMC or on RamFVCC, and it's not really your boards' fault but more that Ian's computer needs some new capacitors?
There must be a bit of variance between Ian's and my A3000 but his machine works with other expansions.

The problem is the signals on the A3000 memory bus aren't within TTL spec and this brand new DRAM is reacting to the glitches. I have a different buffer option which has more noise tolerance so Ian is going to test that. If that works then I can use this RAM - if not then I think this RAM chip will just never work on an A3000 :(

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vanpeebles
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Re: New A3000 4MB memory

Post by vanpeebles » Mon Nov 12, 2018 11:48 am

Is anyone working on anything that would replace the turboram addon for the A3010? That was my one big regret with the A3010. I'd saved up enough, and my mam rang Simtek only for them to have just discontinued it, due to lack of quality ram supplies. That bit extra performance would of been great!

cmorley
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Re: New A3000 4MB memory

Post by cmorley » Sat Nov 17, 2018 1:30 pm

IanS has my original buffered test board with 11 individual buffers. I redrew the board (again) to match this test board which runs on my A3000 fine. This is the last option I am going to try...

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cmorley
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Re: New A3000 4MB memory

Post by cmorley » Sun Nov 18, 2018 4:25 pm

Ian has done a bunch of testing and the results have convinced me to order the issue 3 PCBs. They should be here early December.

I shouldn't have changed the buffer part between the prototype and issue 2. I wanted to make them easier to make. #-o

cmorley
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Re: New A3000 4MB memory

Post by cmorley » Sat Nov 24, 2018 7:22 am

Update: (Latest) PCBs are on their way from China :) They usually take about a week airmail.

cmorley
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Re: New A3000 4MB memory

Post by cmorley » Tue Dec 04, 2018 3:25 pm

The boards arrived today so I built one up to start testing. So far so good. I'll post one to IanS to see if it works in his computer.

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IanS
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Re: New A3000 4MB memory

Post by IanS » Wed Dec 05, 2018 6:22 pm

cmorley wrote:
Tue Dec 04, 2018 3:25 pm
The boards arrived today so I built one up to start testing. So far so good. I'll post one to IanS to see if it works in his computer.
Board arrived today, all tests passed so far. Looking good.

cmorley
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Re: New A3000 4MB memory

Post by cmorley » Thu Dec 06, 2018 9:32 pm

Ian has been busy testing and reports back zero errors! We've called it fixed now.

I'll update the sale thread. Batch one is built up, I have 11 boards in total (which I think is the exact number). I'll order more blank PCBs soon so batch 2 early/mid January I think.

cmorley
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Re: New A3000 4MB memory

Post by cmorley » Fri Dec 07, 2018 1:13 pm

Batch 1 ready for final test and shipping :)
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