SDRAM board

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JimDrew
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Re: SDRAM board

Postby JimDrew » Tue Dec 03, 2019 9:35 pm

Well, today I received my mass produced DE-10 SDRAM boards. These all have -6TIN memory chips that were shipped from Alliance directly to the PCBA house I use (I setup the shipment). The samples I got were 1833 date code and worked up to 150MHz without any issues. The boards I received today have 1842 date codes and guess what?.. they all fail at anything >80MHz using the latest 'mem_test' app. HOWEVER, they all pass at 140MHz (and somewhat at 150MHz) using the original 'memtest_140MHz' and 'memtest_150MHz' apps. So, I decided to try the boards that do pass at 150MHz (using the latest 'mem_test' app) with the older apps and they work, but only using 'memtest_130MHz' and 'memtest_140MHz' (they fail with 'memtest_150MHz'). Has anyone else with the boards that seem to fail at >80MHz tried the older apps to see what their results are? Maybe there is some slight timing differences between revisions of chips? I am chatting with Alliance about this to see if they change things ever.
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Re: SDRAM board

Postby Nat » Wed Dec 04, 2019 12:36 pm

Concerning testing of the 128MB SDRAM modules, the older versions of the memory test application I do not think even test the full 128MB of memory, so are ineffective as a test.

The older versions certainly offer less accurate testing and reporting of errors with 32MB modules when I have tested them in the past, I have not tested any of my 128MB modules with the earlier versions, as far as I am aware the current release is what's recommended for testing all memory modules.

memtest_20190920.rbf is what I use.

Real world testing is useful, my test procedure is as follows for my 128MB modules, test with the Archie core, Minimig core, GBA core, Neo Geo core, and specifically Metal Slug 3 and the Bad Apple demo on the Neo Geo core. Hope this might be of use.

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Re: SDRAM board

Postby JimDrew » Wed Dec 04, 2019 5:48 pm

I believe the older test apps (black screen background, not the blue version) do test the SDRAM using the main frame work (I could be wrong here, I have not looked at any code).

I have tested the Archie core and Minimig cores and they work fine. I have not setup a GBA or Neo Geo cores yet. I will do that. I know that the boot menu uses a 100MHz SDRAM speed, and that works.
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Re: SDRAM board

Postby TWINKYTWONKA » Thu Dec 05, 2019 9:56 am

Nat wrote:Concerning testing of the 128MB SDRAM modules, the older versions of the memory test application I do not think even test the full 128MB of memory, so are ineffective as a test.

The older versions certainly offer less accurate testing and reporting of errors with 32MB modules when I have tested them in the past, I have not tested any of my 128MB modules with the earlier versions, as far as I am aware the current release is what's recommended for testing all memory modules.

memtest_20190920.rbf is what I use.

Real world testing is useful, my test procedure is as follows for my 128MB modules, test with the Archie core, Minimig core, GBA core, Neo Geo core, and specifically Metal Slug 3 and the Bad Apple demo on the Neo Geo core. Hope this might be of use.


im swaying towards this real world testing as no one is going to play the memory test core game ;)

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Re: SDRAM board

Postby JimDrew » Thu Dec 05, 2019 4:54 pm

Probably a good idea, especially since the DE-10 Nano board itself plays a huge role in what memory modules will pass at different speeds.
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Re: SDRAM board

Postby Sorgelig » Thu Dec 05, 2019 7:37 pm

Test version with new clocking. It should be consistent among all clocks.
memtest_ddio.zip
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Re: SDRAM board

Postby JimDrew » Fri Dec 06, 2019 12:13 am

With this version, 32MB Alliance based memory chips fail at 167MHz and 32MB Winbond based memory chips fail at 167MHz and 160MHz. All other memory test programs pass fine at 167MHz with the same Alliance and Winbond modules. So, this seems to be a step backwards.
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Re: SDRAM board

Postby Newsdee » Fri Dec 06, 2019 10:03 am

JimDrew wrote:With this version, 32MB Alliance based memory chips fail at 167MHz and 32MB Winbond based memory chips fail at 167MHz and 160MHz. All other memory test programs pass fine at 167MHz with the same Alliance and Winbond modules. So, this seems to be a step backwards.

Isn't the Alliance chip rated for 166Mhz max? I think some people mentioned that on discord.

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Re: SDRAM board

Postby Sorgelig » Fri Dec 06, 2019 11:12 am

I don't expect any core using SDRAM with higher than 130MHz. To close the timings on 167MHz i had to pipeline all signals which is ok for testing, but for real core gives a high latency rendering such high speed useless as it works slower for random access. For burst and high speed there is DDR3 memory instead.
The build above has more consistency among all frequencies so it should not have errors on lower frequencies if higher frequency is passed.

having differences on highest frequencies for different modules is even better in terms of seeing the differences. If everything passes at 167MHz you can't tell which one is better :)

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Re: SDRAM board

Postby JimDrew » Fri Dec 06, 2019 7:12 pm

OK, thanks for the explanation. What I don't understand is if you have two different brand chips that clearly will handle >=160MHz, why one fails at 160MHz and one doesn't.
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Re: SDRAM board

Postby Sorgelig » Fri Dec 06, 2019 9:22 pm

because 40pin GPIO connector is not supposed to drive the SDRAM originally.

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Re: SDRAM board

Postby JimDrew » Sat Dec 07, 2019 2:38 am

I agree it is a nightmare to try to do proper impedance matching, especially with a right angle connector. However, that doesn't answer the question of why there is a difference in the brands of chips?

Maybe it would be better to use a 200MHz+ (2ns R/W time) BGA SDRAM module. There are a couple of different 256MB and 512MB boards being developed for the DE-10 Nano, although those are more about having large amounts of memory at around 100MHz and not for something super fast.
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Re: SDRAM board

Postby Nat » Sat Dec 07, 2019 9:48 am

I though some of the appeal of the MiSTer project, is in fact anyone can create the SDRAM boards and other add-on expansion boards at home with little in the way of specialised tools, just a soldering iron and some patience along with the PCB and components is all you need.

As soon as you enter into using BGA based SDRAM chips, this route then excludes many from being able to produce the memory modules, because suddenly the equipment requirement jumps to only those with a BGA rework station, which will be a much smaller amount.

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Re: SDRAM board

Postby Sorgelig » Sat Dec 07, 2019 12:52 pm

No problem with right angled connector. Everything works as expected.

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Re: SDRAM board

Postby JimDrew » Sat Dec 07, 2019 9:38 pm

A right angle connector has a different impedance requirement than a straight (vertical) connector due to the different length of pins on one side of the connector. Although it doesn't seem like much, it does make a big difference in the layout.
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Re: SDRAM board

Postby mnielsenau » Sat Dec 14, 2019 7:02 am

Sorgelig wrote:Test version with new clocking. It should be consistent among all clocks.
memtest_ddio.zip


Hey Sorgelig,

Thanks for uploading this core here.

I was wondering what changes were made to this version of the memory test core? I have a 128MB memory board that has errors consistently at 130MHz with version 20190920 but with the memtest_ddio it worked fine at 140MHz for well over 30 min.

Is this memtest_ddio version going to be the new memory test core now and if so are you going to release it on github? :)

Cheers,

M.

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Re: SDRAM board

Postby djmartins » Sat Dec 21, 2019 2:20 am

Sorgelig wrote:No problem with right angled connector. Everything works as expected.


I just received an Alliance IC and soldered up a 32Mb board to replace the Winbond ones I also hand soldered.
Works fine and passes 160MHz and fixed the sprite issues with the two jotego cores.
BGA IC are not doable with simple hand soldering but what was designed does in fact WORKS AS EXPECTED as stated above
and the right angle allows a nicely compact MiSTer.
MiSTer doesn't need nor can it use 200MHz memory so why change something that works for an overspec'd hard to solder IC?

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Re: SDRAM board

Postby implodetee » Fri Dec 27, 2019 5:34 am

Hobbyist/enthusiast here. Ordered the 128MB xxsd board (hardware alternative) by @antoniovillena via oshpark, using AS4C32M16SB-7TCN x2 and C0805C104J5RECTU. Using the 20190920 memtest, the memtest would succeed for about a minute at 140 and then devolve to ~90 over time, but remain stable. In real-world tests, I ran Metal Slug 5 and Garou for >1hr plus each with no issues.

At first I thought my problems with memtest 20190920 was the components/soldering/boards; I redid a few things, etc. but it appears perhaps it was the timings?

Using the latest memtest_ddio posted by Sorgelig, I'm able to run at 140 for at least 30 minutes (so far, need to run more tests) without any problems.

Thanks everyone for your work on these boards and the cores. :cheers:

edit: just played through MS5 again, from beginning to end, no issues. Thanks @Sorgelig for correcting/adjusting the timings!
Last edited by implodetee on Fri Dec 27, 2019 7:18 am, edited 2 times in total.

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Re: SDRAM board

Postby Sorgelig » Fri Dec 27, 2019 7:16 am

latest memtest release is a further improvements of memtest_ddio.

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Re: SDRAM board

Postby RETR0Gamer » Sat Dec 28, 2019 12:27 am

Hey Everyone! Thanks for all the work you guys are putting into this project. I recently got into Mister and I love it. I current have a cheap 32MB Sdram module and I wanted to try my hand at building my own 128MB Sdram module. Anyway, I ordered some of the v2.4 pcbs from OSHPARK. The files had some naming errors when trying to upload the gerber so I emailed their support and they renamed them and sent me back the fixed file for their system. I just received the boards and I was reading through this forum and saw that a few people said their boards from OSHPARK weren't manufactured correctly and had to ask for a refund. So now I'm concerned that my boards are going to have issues, too. Can you take a look at these pics of my boards and see if there are any obvious issues you can spot with them? Last thing I want to do is spend the time building these and have them be faulty. Thanks!

https://ibb.co/vqcHSZD
https://ibb.co/Fbw9yFW
https://ibb.co/JRQB7zh
https://ibb.co/xhcxxpY

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Re: SDRAM board

Postby Sorgelig » Sat Dec 28, 2019 2:07 pm

RETR0Gamer wrote:Hey Everyone! Thanks for all the work you guys are putting into this project. I recently got into Mister and I love it. I current have a cheap 32MB Sdram module and I wanted to try my hand at building my own 128MB Sdram module. Anyway, I ordered some of the v2.4 pcbs from OSHPARK. The files had some naming errors when trying to upload the gerber so I emailed their support and they renamed them and sent me back the fixed file for their system. I just received the boards and I was reading through this forum and saw that a few people said their boards from OSHPARK weren't manufactured correctly and had to ask for a refund. So now I'm concerned that my boards are going to have issues, too. Can you take a look at these pics of my boards and see if there are any obvious issues you can spot with them? Last thing I want to do is spend the time building these and have them be faulty. Thanks!

https://ibb.co/vqcHSZD
https://ibb.co/Fbw9yFW
https://ibb.co/JRQB7zh
https://ibb.co/xhcxxpY

i see the same problem of wrong trace below the word "SIDE". Overall quality is bad too. Milling is awful..

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Re: SDRAM board

Postby Nat » Sat Dec 28, 2019 3:09 pm

Ask for a refund, they will not work.

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Re: SDRAM board

Postby kolla » Sun Dec 29, 2019 8:25 am

Huh, I have ordered my share of boards from OSHPARK, but nothing ever looked like this - these don't even look new 8O
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Re: SDRAM board

Postby RETR0Gamer » Tue Dec 31, 2019 12:17 am

Ah jeez. Well, I emailed them and told them that the manufacturing on this board is not correct. Hopefully they will refund me or give me credit for future orders.

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Re: SDRAM board

Postby RETR0Gamer » Tue Dec 31, 2019 7:19 am

Sorry to double post, but can someone please post some pics of a 128MB sdram board that is manufactured correctly. I want to be able to show them in case they don't want to help me out. Thanks.


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