SDRAM board

https://github.com/MiSTer-devel/Main_MiSTer/wiki

Moderators: Mug UK, Zorro 2, spiny, Greenious, Sorgelig, Moderator Team

Locked
Nat
Atari nerd
Atari nerd
Posts: 49
Joined: Fri Sep 20, 2019 12:19 pm
Location: United Kingdom
Contact:

Re: SDRAM board

Post by Nat »

I've found the 4 layer 128MB printed circuit boards from PCBWAY although more expensive, have performed well.
MiSTerFPGA Add-On Boards: UK based, low cost worldwide shipping.
https://MiSTerFPGA.co.uk/
lolof
Atariator
Atariator
Posts: 26
Joined: Sat Oct 06, 2018 9:21 pm

Re: SDRAM board

Post by lolof »

From my experience, JLCPCB ask by email in which order has to be the inner layer if it's not clear......
Sorgelig
Ultimate Atarian
Ultimate Atarian
Posts: 6348
Joined: Mon Dec 14, 2015 10:51 am
Location: Russia/Taiwan

Re: SDRAM board

Post by Sorgelig »

Talked with 2 sellers about 128MB boards. They have ZERO failure rates. They use JLCPCB.
So there is no problem with design and PCB manufacturing. Problem is in soldering.

Make sure you don't modify the boards. If some additional software is used for panelizing, then it may modify some parameters of original board and make it behave differently in tests and cores.
JimDrew
Atari Super Hero
Atari Super Hero
Posts: 865
Joined: Mon Nov 04, 2013 5:23 pm

Re: SDRAM board

Post by JimDrew »

The reliability really depends on the DE-10 Nano board itself. It's something that I have asked Terasic to look into. I have 128MB SDRAM plug-in modules that I designed as well as the original 128MB design that is in the MiSTer repo. Both designs work fine in three of the five DE-10 Nano boards, passing at 150MHz with no problems for literally days. The other two DE-10 Nano boards won't pass at anything over 120MHz, and one periodically won't pass at 110MHz. I can rotate the modules between boards with the exact same results. The problem follows the DE-10 Nano board itself, not the SDRAM module. The same holds true for 32MB, 64MB, and 256MB SDRAM modules. If this were a simple soldering problem then the speed issue would follow the module, not the DE-10 Nano board.
I am the flux ninja
Grabulosaure
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 108
Joined: Tue Sep 05, 2017 9:35 pm
Contact:

Re: SDRAM board

Post by Grabulosaure »

JimDrew wrote:The reliability really depends on the DE-10 Nano board itself. It's something that I have asked Terasic to look into. I have 128MB SDRAM plug-in modules that I designed as well as the original 128MB design that is in the MiSTer repo. Both designs work fine in three of the five DE-10 Nano boards, passing at 150MHz with no problems for literally days. The other two DE-10 Nano boards won't pass at anything over 120MHz, and one periodically won't pass at 110MHz. I can rotate the modules between boards with the exact same results. The problem follows the DE-10 Nano board itself, not the SDRAM module. The same holds true for 32MB, 64MB, and 256MB SDRAM modules. If this were a simple soldering problem then the speed issue would follow the module, not the DE-10 Nano board.
I have tried to add ring oscillators as a way to evaluate temperature, but what it really measures is chip switching time :
http://temlib.org/pub/mister/Genesis_thermo.rbf

Chip performance depends on temperature, power supply and actual variations of the silicon (just like PC overclockers change voltages, cooling...). Maybe it could be possible to correlate the issues with SDRAM boards with variations in ring oscillators frequencies. These variations may be caused not necessarly by a lower grade chip, but because, for example, the internal low voltage power supplies (2.5V, 1V...) are a set a little bit lower.
User avatar
gojira54
Atari nerd
Atari nerd
Posts: 44
Joined: Mon Oct 29, 2018 5:40 pm

Re: SDRAM board

Post by gojira54 »

For what it's worth I made a small batch - all passed 150 after I soldered them properly, some needed reflowing after first attempt.
My setup was PCBs from PCBway, components all bought from RS/digikey so no moody stuff and DE-10 is running off of a 4A rated PSU.
Please do not take it personal, my lawyer has policies
JimDrew
Atari Super Hero
Atari Super Hero
Posts: 865
Joined: Mon Nov 04, 2013 5:23 pm

Re: SDRAM board

Post by JimDrew »

I have tried various power supply options, different cables, VGA vs. HDMI, etc. The only difference is with the DE-10 Nano board themselves. I have 6 more DE-10 Nano boards coming that I will be testing for Terasic.
I am the flux ninja
zerohimself
Retro freak
Retro freak
Posts: 16
Joined: Wed Dec 12, 2018 10:09 pm

Re: SDRAM board

Post by zerohimself »

Sorgelig wrote:I recommend to try to desolder the chips from faulty module, then inspect under magnifying glass the soldering of connector. Then clean it again from flux (by IPA or Ethanol). Then solder back the chips again. Inspect by magnifying glass if there any hanging legs of chips. If any soldering point of connector has bubble, then RAN chip won't lay flat, and legs may hang on the air. It's not a problem actually, but soldering of chip must be careful as some legs won't be soldered. Although you've told the cores work fine (besides the memtest), it's better to try to resolder just to make sure everything is right.
I will check with one seller who soldered many 2.4 and 2.5 if he had noticeable failure rates..
I solder under a microscope and can confirm that I have no "hanging" legs. My new 2.5 pcb's from PCBWay continue to have almost zero issues. I am certain it was the PCB's from jlcpcb. I just don't understand why they work for some people, and why i'm having so many issues with them. I mainly wanted to warn others who are having issues that it may be worth getting a small batch from another PCB fab to see if it eliminates their problems.

Today I did a test of a 2.4 pcb(JLCPCB), I desoldered (with hot air), and resoldered (by hand with my iron) the chips, and it still had horrible results @ 130mhz. I then desoldered the chips and placed them on a v2.5 pcb(PCBWAY), where they now test at 150 (which is pretty good for a -7tin!!).

Please do not think that I am blaming your design. I really feel that a mistake was made somewhere somehow with my PCB's from JLCPCB. I would much rather use them, as they are cheaper, but I have wasted a lot of time, effort, and money on PCB's from them, that just don't work. I made no modifications, I allowed jlcpcb to panelize. Maybe there is some kind of mistake in my settings? (please let me know if you see any mistakes here!)

(correction, I did find one difference, with PCBway i used TG150 FR4 -- could this have caused the difference?)

JLCPCB settings:

Code: Select all

Gerber file: sdram_xsd_2.4_Y11

Build Time: 4-5 days

Layers: 4

Dimension: 23mm*51mm

PCB Qty: 10

PCB Thickness: 1.6

Impedance: yes JLC7628

PCB Color: Blue

Surface Finish: HASL(with lead)

Copper Weight: 1

Gold Fingers: No

Material Details: FR4-Standard Tg 130-140C

Panel By JLCPCB: X:2*Y:4
Edge Rails: On 2 Sides mm

Panel size:【X: 102mm Y: 102mm 】

Flying Probe Test:Fully Test

Castellated Holes:no
I feel that soldering is not the issue here, how can I have a failure rate of around 50-60% with all blue pcbs from jlcpcb, and have a failure rate of 4% with blue pcbs from pcbway? I could be wrong, but that tells me that it is something with those PCB's. I have made hundreds of sdram modules, with no issues before this batch of pcb's.

And to save others from making a mistake,I have only been asked about the layer order one time, and it was the most recent PCBway order (that i have not received yet, I just specified 1 2 3 4, as I never saw any indication to change anything.) If this is not correct, please let me know( If that is wrong, I would feel pretty stupid, but hopefully it would save others from the hassle I went through).
Sorgelig
Ultimate Atarian
Ultimate Atarian
Posts: 6348
Joined: Mon Dec 14, 2015 10:51 am
Location: Russia/Taiwan

Re: SDRAM board

Post by Sorgelig »

So, you use panelisation from JLCPCB. I never used this feature. So, probably something wrong with this. They may use panelisation software which may alter some parameters.
This is the only difference i see.
zerohimself
Retro freak
Retro freak
Posts: 16
Joined: Wed Dec 12, 2018 10:09 pm

Re: SDRAM board

Post by zerohimself »

Sorgelig wrote:So, you use panelisation from JLCPCB. I never used this feature. So, probably something wrong with this. They may use panelisation software which may alter some parameters.
This is the only difference i see.
Well, for us larger sellers, it makes the most sense to panelize. I had no problem with panelization from PCBway, and other sellers i know have successfully used jlcpcb's panelization on these pcb's as well. I'll ask them for their specific settings and see if I can find a difference there. If not, I may just use PCBway for my 4 layers, and keep getting my normal 2layers from jlcpcb.
Sorgelig
Ultimate Atarian
Ultimate Atarian
Posts: 6348
Joined: Mon Dec 14, 2015 10:51 am
Location: Russia/Taiwan

Re: SDRAM board

Post by Sorgelig »

For large quantities PCBWay has good price as it doesn't grow fast with quantities, especially for 4-layer boards. I remember they had no difference (or almost no difference) when i tried to select like 10 or 40 pieces.

I don't think you will find out the differece from JLCPCB reply. Most likely the person who will reply, is not aware of specifics. You can try to order the boards without panelisation.

Btw, the difference between v2.4 and v2.5 is clearance from pads to ground plane. So basically they have no difference. v2.5 just more forgiving for soldering.
zerohimself
Retro freak
Retro freak
Posts: 16
Joined: Wed Dec 12, 2018 10:09 pm

Re: SDRAM board

Post by zerohimself »

Sorgelig wrote:For large quantities PCBWay has good price as it doesn't grow fast with quantities, especially for 4-layer boards. I remember they had no difference (or almost no difference) when i tried to select like 10 or 40 pieces.

I don't think you will find out the differece from JLCPCB reply. Most likely the person who will reply, is not aware of specifics. You can try to order the boards without panelisation.

Btw, the difference between v2.4 and v2.5 is clearance from pads to ground plane. So basically they have no difference. v2.5 just more forgiving for soldering.
Everyone I have talked to who had no issues with their PCB's, did not panelize. I am begining to suspect it was JLCPCB's panelization settings. I have had not issues with PCBway's panelization so far, I will let everyone know if i have any issues with their panelization process.

Thank you for helping me sort this out. For anyone new, trying to save a few bucks, I wouldn't trust JLCPCB to panelize your order (but to be fair, this may have been due to my lack of knowledge about the process).
JimDrew
Atari Super Hero
Atari Super Hero
Posts: 865
Joined: Mon Nov 04, 2013 5:23 pm

Re: SDRAM board

Post by JimDrew »

I don't use panellization through JLCPCB, PCBWAY, PCBEXPRESS, etc. because I don't use them for mass production. I only get prototypes through these companies.
I am the flux ninja
MrKarai
Atarian
Atarian
Posts: 8
Joined: Wed Oct 30, 2019 2:29 pm

Re: SDRAM board

Post by MrKarai »

Ever since the NeoGeo core was released, I am obsessed with the idea of putting my MiSTer (just the DE10 and a ram module) into a NeoGeo X dock's case. Problem is the height of the vertical ram module. Hence I am looking for a 128 MB horizontal outward module but it seems everyone is just doing vertical nowadays. Are there 40 pin adapters that would work??
antoniovillena
Atari User
Atari User
Posts: 43
Joined: Mon Oct 24, 2016 9:11 pm

Re: SDRAM board

Post by antoniovillena »

MrKarai wrote:Ever since the NeoGeo core was released, I am obsessed with the idea of putting my MiSTer (just the DE10 and a ram module) into a NeoGeo X dock's case. Problem is the height of the vertical ram module. Hence I am looking for a 128 MB horizontal outward module but it seems everyone is just doing vertical nowadays. Are there 40 pin adapters that would work??
I sell horizontal (XXS) and less height vertical ones (XXSV) here.
JimDrew
Atari Super Hero
Atari Super Hero
Posts: 865
Joined: Mon Nov 04, 2013 5:23 pm

Re: SDRAM board

Post by JimDrew »

I now have 10 DE-10 Nano boards, and they pretty much all behave differently. There is one thing in common that I have noticed though... with the 128MB SDRAM module (no matter who makes it), it passes generally ok at 150MHz and always at 140MHz, but not at 130MHz or sometimes at 120MHz! It's like the timing is off or something with lower memory speeds with some (most?) boards. When repeating this test over and over again on various DE-10 Nano boards (using the exact same SDRAM board), the results are absolutely repeatable over hours of testing. 130MHz has a large number of errors over an hour of testing - about 60 errors +/-1 every time. 150MHz might be 5 to 6 errors, 140MHz is 0. 160MHz is a few hundred. 120MHz is 2 to 3. I tried different SDRAM boards with the same results. Just an observation I thought I would point out. :) I do have one magical DE-10 board that passes at all clock speeds with any SDRAM board I put in it. It might be nice to have a way to tweak the memory controller to account for the differences in the DE-10 Nano boards.
I am the flux ninja
tomywong
Atarian
Atarian
Posts: 8
Joined: Sat Oct 29, 2016 8:46 am

Re: SDRAM board

Post by tomywong »

I soldered one 128M SDRAM. It only pass 80MHZ maximum. From the schematic, it use 1uf capacitor. Is it problem ? Or maybe my sdram bad.
Nat
Atari nerd
Atari nerd
Posts: 49
Joined: Fri Sep 20, 2019 12:19 pm
Location: United Kingdom
Contact:

Re: SDRAM board

Post by Nat »

tomywong wrote:I soldered one 128M SDRAM. It only pass 80MHZ maximum. From the schematic, it use 1uf capacitor. Is it problem ? Or maybe my sdram bad.
Use the following capacitors on your board:

Top Row : 10uf, 0.1uf, 10uf, 0.1uf

Bottom Rom : 10uf, 1uf, 1uf, 10uf, 10uf, 1uf, 1uf, 10uf

Hope this helps.
MiSTerFPGA Add-On Boards: UK based, low cost worldwide shipping.
https://MiSTerFPGA.co.uk/
User avatar
witchmaster
Captain Atari
Captain Atari
Posts: 150
Joined: Wed Jun 15, 2011 10:50 am

Re: SDRAM board

Post by witchmaster »

tomywong wrote:I soldered one 128M SDRAM. It only pass 80MHZ maximum. From the schematic, it use 1uf capacitor. Is it problem ? Or maybe my sdram bad.
The soldering is probably not up to par.
JimDrew
Atari Super Hero
Atari Super Hero
Posts: 865
Joined: Mon Nov 04, 2013 5:23 pm

Re: SDRAM board

Post by JimDrew »

The boards need to be thoroughly clean. If you have access to a sonic cleaner, this is the best way to clean them. Use a mild solvent that will break down solder flux.
I am the flux ninja
digitron
Atari maniac
Atari maniac
Posts: 92
Joined: Sat Apr 20, 2019 7:27 pm

Re: SDRAM board

Post by digitron »

The silkscreen on the jlcpcb boards is poor quality..
TWINKYTWONKA
Atariator
Atariator
Posts: 25
Joined: Wed Dec 12, 2018 8:18 pm

Re: SDRAM board

Post by TWINKYTWONKA »

digitron wrote:The silkscreen on the jlcpcb boards is poor quality..
I think this is correct and supports my own findings. Ive found that on jlpcb boards if you solder at 310 and don't drag solder you will get 100% success rate and even the 7ctn chips will test at 150mhz ( which they shouldn't i know). However, if you dwell too much and especially at higher temps then you damage the boards. I got someone at work to check these boards out under their fancy microscope and confirm this. Sadly i didn't keep the images :(

So in summary. If you don't want to spend an evening soldering,checking, soldering,checking, soldering,checking etc then solder at 310C and don't dwell.

hope this helps someone
Sorgelig
Ultimate Atarian
Ultimate Atarian
Posts: 6348
Joined: Mon Dec 14, 2015 10:51 am
Location: Russia/Taiwan

Re: SDRAM board

Post by Sorgelig »

TWINKYTWONKA wrote: I think this is correct and supports my own findings. Ive found that on jlpcb boards if you solder at 310 and don't drag solder you will get 100% success rate and even the 7ctn chips will test at 150mhz ( which they shouldn't i know). However, if you dwell too much and especially at higher temps then you damage the boards. I got someone at work to check these boards out under their fancy microscope and confirm this. Sadly i didn't keep the images :(

So in summary. If you don't want to spend an evening soldering,checking, soldering,checking, soldering,checking etc then solder at 310C and don't dwell.

hope this helps someone
I cannot confirm this. I use 400C for manual soldering and have no problems. Time after time i even desolder the chips by hot air and solder back. Still no problems.
I think result may depends on flux used and how good it was cleaned.
terminator2k2
Atariator
Atariator
Posts: 27
Joined: Sat Dec 22, 2018 10:23 pm

Re: SDRAM board

Post by terminator2k2 »

Sorgelig wrote:
TWINKYTWONKA wrote: I think this is correct and supports my own findings. Ive found that on jlpcb boards if you solder at 310 and don't drag solder you will get 100% success rate and even the 7ctn chips will test at 150mhz ( which they shouldn't i know). However, if you dwell too much and especially at higher temps then you damage the boards. I got someone at work to check these boards out under their fancy microscope and confirm this. Sadly i didn't keep the images :(

So in summary. If you don't want to spend an evening soldering,checking, soldering,checking, soldering,checking etc then solder at 310C and don't dwell.

hope this helps someone
I cannot confirm this. I use 400C for manual soldering and have no problems. Time after time i even desolder the chips by hot air and solder back. Still no problems.
I think result may depends on flux used and how good it was cleaned.
and i was jumped on , on classic gaming discord for saying i soldered @ 400c haha , funny how folks are quick to jump to there own conclusions, ive been soldering for years at these temps and never had any problems, also used chipquick to re-use smd parts
MrKarai
Atarian
Atarian
Posts: 8
Joined: Wed Oct 30, 2019 2:29 pm

Re: SDRAM board

Post by MrKarai »

antoniovillena wrote:
MrKarai wrote:Ever since the NeoGeo core was released, I am obsessed with the idea of putting my MiSTer (just the DE10 and a ram module) into a NeoGeo X dock's case. Problem is the height of the vertical ram module. Hence I am looking for a 128 MB horizontal outward module but it seems everyone is just doing vertical nowadays. Are there 40 pin adapters that would work??
I sell horizontal (XXS) and less height vertical ones (XXSV) here.
Bought one, thanks a lot for the reference!
Locked

Return to “MiSTer”