TF530 memory options

[kludge]

It seems I’m getting a TF530 PCB as well as CPLD’s and other miscellaneous parts as a gift from a friend. The problem is that he can’t seem to find the SRAM.

I thought I was going to build it, even though the 530 is on it’s way out, but I need to source at least the RAM for it.

Do we have any other confirmed configurations other than Alliance AS7C4096A-12TCN? What I’m looking for is, you might have guessed it, a cheaper option (as well as hints on 4 MB hacks) :)

Edit: Found the Wiki. Seems to have been updated since I checked a long time ago :)

https://github.com/terriblefire/tf530/w ... -Ram-Chips

It would still be nice to hear if anyone have more recent experience with it.

Edit again: He has found the Alliance RAM. He’s been looking for them for about a month, and as soon as I started this thread he found them.

[terriblefire]

I found the RAM in seconds...

AS7C4096A-12TCN

https://www.mouser.co.uk/ProductDetail/ ... TdlGR20%3d

[kludge]

I think we have a case of miscommunication here. :)

First I was looking for cheaper options than the Alliance RAM because my friend couldn’t find the RAM that he bought. Then he found them. So it was not a case of finding Alliance RAM to buy :D

[terriblefire]

I think we have a case of miscommunication here. :)

First I was looking for cheaper options than the Alliance RAM because my friend couldn’t find the RAM that he bought. Then he found them. So it was not a case of finding Alliance RAM to buy :D

Ah ok. Sorry. I've never used anything except the alliance ram because people reported issues with other chips.

[alenppc]

IS61C5128AL doesn't work properly, don't use it

[kludge]

Ah ok. Sorry. I've never used anything except the alliance ram because people reported issues with other chips.

No problem.

As he found the Alliance RAM I'm all set anyway. I'll probably be back with questions when I've started to build it :)

[bwana]

Hi all,

I've build a TF530 with AS7C4096A-12TI (not AS7C4096A-12TIN) RAM chips (with a 40Mhz quartz).
Pin 25 of these chips were raised to avoid feeding A21 on the NC pin.

As expected, the TF530 doesn't work well (these RAM are marked as non-working on the wiki).
I've managed to boot (with stability issues) my A500 with these RAM using the latest firmware binaries (tf530_2018_11_17_beta) but not with tf530_2018_11_4_beta. Sysinfo reports 2MB of fast RAM and a expected speed.

I don't really understand why the board is ok with AS7C4096A-12TIN and NOT with AS7C4096A-12TI.
According to the datasheet, the only difference is a lead free version for the TIN version. All electrical characteristics are the same.

I wonder if there is no timing issue with RAM access in the verilog sources.

Where I can find the latest CPLD sources for the TF530? (the one used to synthesis tf530_2018_11_17_beta binaries).

Thanks a lot!

[terriblefire]

Those ram chips will not work and I no longer develop the TF530 board.

Latest sources are closed source because of how some people behave.

EDIT: For record the same timings work with 55ns RAM in the TF534.. so it’s not that the timings are too fast. Basically I published not to use that RAM for a reason.

[terriblefire]

The best option you have at this point is to try using X7R 1uF caps under the RAM chips and CPLD. Its likely not enough decoupling that’s the issue rather than timing.

[bwana]

Dear terriblefire,

Thanks for the explenation, I'll give a try with 1uF decoupling capacitors.

Cheers