MiSTer FPGA Forum

Hello! I might have made a mistake.

As we all know a De10 Nano can be hard to get a hold of right now. And i thought i had found a new way to get one that nobody was really talking about when i saw this Self-Balancing Robot kit that includes a de10 nano.

https://www.digikey.com/en/product-high ... opment-kit

It was also slightly cheaper than the Cloud Connectivity kit. So i jumped at the opportunity and order one.
Isn't it cute?



But now when i look closer i discover something that i (unfortunately) did not see before i ordered. There is a slight difference to this de10 nano board compared to the stock one. The top 40 pin GPIO header is located on the bottom of the board instead of the top. This so it can connect easily to the balancing board below.


So this is a problem. But is it a big problem? It seems to me the solution is pretty straight forward. I just have to de-solder the header from the bottom side and solder it on again on the top.

But this makes me nervous. I have not soldered anything since many many years ago back in school. And never anything as tiny as this.
Is there a risk that the components on the board might take damage from the high heat when soldering?

Im very new to this type of thing. Anyone who have some good advice?

Desoldering GPIO headers can be a pain, especially without decent tools. Unless you have a decent desoldering gun and experience I wouldn't risk it on such an expensive piece of kit, there's a very real risk of lifting a pad or damaging a trace.

Find someone with a desoldering gun and experience that can help, it's not a difficult job with the right tools.

Hi OnkelB.

Here is another one (myself) that thought the same. The difference is that even if I ordered one month ago, I will open and start to experiment from 25th of December. Sorry but traditions are important to me, so i cannot help or even share experiences until then.

But, boys, I was really surprised by your post, at least as much as you was surprised when finding the difference : the idea of a different DE10-Nano board used for a kit that officially includes it disturbs me.

Please post here if you solve the problem and notice more differences (PM is not enable for noobs like us ).

rvanzo1971 wrote: ↑Wed Nov 09, 2022 7:39 pm Hi OnkelB.

Here is another one (myself) that thought the same. The difference is that even if I ordered one month ago, I will open and start to experiment from 25th of December. Sorry but traditions are important to me, so i cannot help or even share experiences until then.

But, boys, I was really surprised by your post, at least as much as you was surprised when finding the difference : the idea of a different DE10-Nano board used for a kit that officially includes it disturbs me.

Please post here if you solve the problem and notice more differences (PM is not enable for noobs like us ).

Good to know i am not alone in this

I have not noticed any other differences so far. And i guess you can actually use it in its current state for a Mister build. It just would be clunky as all hell with the SDRAM module pointing straight down. It wouldn't fit in any existing cases.

But maybe a possible solution is to simply connect the GPIO header to the SDRAM module with a ribbon cable. I have a build with the Ironclad plus in mind and that might just fit. I will have to wait until the Ironclad arrives to see if there is enough space.

AngelicLiver wrote: ↑Wed Nov 09, 2022 7:10 pm Desoldering GPIO headers can be a pain, especially without decent tools. Unless you have a decent desoldering gun and experience I wouldn't risk it on such an expensive piece of kit, there's a very real risk of lifting a pad or damaging a trace.

Find someone with a desoldering gun and experience that can help, it's not a difficult job with the right tools.

That is good advice. I dont think i dare to attempt to do the soldering myself. But i think i know where i could find help.

And that will be my plan B if the ribbon cable dont work out.

And i guess you can actually use it in its current state for a Mister build. It just would be clunky as all hell with the SDRAM module pointing straight down. It wouldn't fit in any existing cases.

Yes, I think so. If I were you, I would attempt anyway, so you know that everything is in order before risking any soldering or possibly destructive mod, . I think the main problem with the clunky layout (apart case compatibility) comes if you want to expand the De10 with the standard I/O, clock, and USB add on boards.

But maybe a possible solution is to simply connect the GPIO header to the SDRAM module with a ribbon cable.

Good Idea, even if it sounds clunky in any case .

OnkelB wrote: ↑Thu Nov 10, 2022 10:23 am

AngelicLiver wrote: ↑Wed Nov 09, 2022 7:10 pm Desoldering GPIO headers can be a pain, especially without decent tools. Unless you have a decent desoldering gun and experience I wouldn't risk it on such an expensive piece of kit, there's a very real risk of lifting a pad or damaging a trace.

Find someone with a desoldering gun and experience that can help, it's not a difficult job with the right tools.

That is good advice. I dont think i dare to attempt to do the soldering myself. But i think i know where i could find help.

And that will be my plan B if the ribbon cable dont work out.

I strongly advise against using a ribbon cable. The SDRAM is extremely sensitive to voltage drops, noise and timing discrepancies. It must be connected directly to the GPIO pins.

Ok i see. I suppose there is a good reason why the RAM is always located directly next to the CPU on computers.
Then soldering it is.

A ribbon cable is pretty cheap so trying and see if it works good enough will not cost much.

And you can easily test the memory with mister memtest https://github.com/MiSTer-devel/MemTest_MiSTer

OnkelB wrote: ↑Thu Nov 10, 2022 10:17 am And i guess you can actually use it in its current state for a Mister build. It just would be clunky as all hell with the SDRAM module pointing straight down. It wouldn't fit in any existing cases.

I don’t think this would work, because there are two rows of pins. If you install the SDRAM upside down socket one will either end up at pin 2 or pin 39, depending on how you rotate it, and socket 2 will be at pin 1 or 40, and so on. If you try doing it with ribbon cables make sure you take that into account.

Yeah, I think you're gonna wreck your RAM if you try that with a straight-through ribbon. And redoing the ribbon cable will involve moving probably every pin.

Soldering would be easier.

First buy a new pin header. Heat up each leg (with a standard soldering iron!) from the top of the board, and pull them out with pliers, one by one. That's the safest, smartest and most non-destructive way of desoldering it. When all pins are out, use a regular solder sucker to clean out all the holes. This is easy to do even for a noob using bad tools.

@C-R-T Having a solder sucker isn't it much simpler (and equally non-destructive) to suck the tin off each one of the leg from the upper side and then remove the loosen header from the bottom?

@OnkelB: any advancement on this?

Yim wrote: ↑Sat Nov 12, 2022 3:52 pm

OnkelB wrote: ↑Thu Nov 10, 2022 10:17 am And i guess you can actually use it in its current state for a Mister build. It just would be clunky as all hell with the SDRAM module pointing straight down. It wouldn't fit in any existing cases.

I don’t think this would work, because there are two rows of pins. If you install the SDRAM upside down socket one will either end up at pin 2 or pin 39, depending on how you rotate it, and socket 2 will be at pin 1 or 40, and so on. If you try doing it with ribbon cables make sure you take that into account.

You're totally right!

rvanzo1971 wrote: ↑Mon Nov 28, 2022 3:53 pm

Yim wrote: ↑Sat Nov 12, 2022 3:52 pm

OnkelB wrote: ↑Thu Nov 10, 2022 10:17 am And i guess you can actually use it in its current state for a Mister build. It just would be clunky as all hell with the SDRAM module pointing straight down. It wouldn't fit in any existing cases.

I don’t think this would work, because there are two rows of pins. If you install the SDRAM upside down socket one will either end up at pin 2 or pin 39, depending on how you rotate it, and socket 2 will be at pin 1 or 40, and so on. If you try doing it with ribbon cables make sure you take that into account.

You're totally right!

Maybe a ribbon cable like this one would do the trick. But female to male if such a thing exists.

rvanzo1971 wrote: ↑Mon Nov 28, 2022 3:51 pm @OnkelB: any advancement on this?

The project is on ice for the moment as im waiting for a few more components that i need to do some soldering on to arrive.

I think im just going to hire a professionell to do all the things i need to solder at the same time if its not to expensive.
I also need to replace a female GPIO on a Raspberry pi with a male one. And add a few pins to a I2S DAC so it can be used with jumper cables.

Probably i could do it myself but i would still have to buy the soldering equipment that i most likely wont use again very much after this. And i wouldn't have to worry about messing up.

Ok thanks for the update.

Write to me if you have news . I'll do it myself after Christmas...

Bye

A ribbon cable is unlikely to work here, maybe a right angle adapter might work?

https://www.technologicalarts.com/produ ... ight-angle

A ribbon cable is unlikely to work here, maybe a right angle adapter might work?

https://www.technologicalarts.com/produ ... ight-angle

I think this is a great idea, but unluckily this does not solve the "pin order" problem underlined by Yim, because pin sequence is mirrored in any case, so there is no way to insert the RAM module respecting the right pin correspondence.

My 2 cents:
I always mark down components that are connected to GND
Sometimes they suck up a lot of heat and the iron/sucker wont work as good.

edit: this thread should be a sticky with a "CAUTION" attached to it, so others do not fall into the same trap.

Hi all,
finally, Christmas came, Santa did his work and I officially got my Mister !

As reported in this thread I had the auto-balancing-robot (source of the DE10-nano and of some fun itself) and a set of standard odd-on boards (USB hub, I/O, 128MB RAM, RTC, and vent).

The de10-nano in the kit has 2 connectors that are soldered on the bottom of the PCB differently than the standard de10-nano:

Problems with using this version with the standard expansion board are of two different orders:

1) Pin order on the connectors is "mirrored", so you cannot attach directly the standard SDRAM module on the bottom of the board (see previous posts).
2) "space" used by the connectors and consequent contacts/shorts of the pins with the USB board, typically placed under the de-nano and connected with the USB bridge. In particular, I have a short bridge, so you can see what I mean with the pictures:

So, given these problems, I decided to go with some desoldering, hoping my experience (not so much exp. unluckly) would be enough to do acceptable quality work avoiding damages to the PCB.

I frankly discourage anyone that has not much experience and at least as good tools as mine from doing the same...

My tools are:

• a manual ( ) desoldering pump

• at least a good quality solder - I have a tiny one for precision and a 110W one for works that need power)

• solder wick

• solder flux

• MUCH PATIENCE

My desoldering pump did not do a good job to suck all the tin, the connector remained very firmly in its place, so I adopted the suggested technique from C-R-T:

Heat up each leg (with a standard soldering iron!) from the top of the board, and pull them out with pliers, one by one. That's the safest, smartest and most non-destructive way of desoldering it

.

Before proceeding, I had to remove the plastic part of the header forcing a bit with a screwdriver on the PCB (a bit risky but I supposed and hoped near the header there were not too fragile tracks).

It was not an easy task, I had to find a way to make some pressure on each pin while heating up. Luckily I discovered the de10-nano is not a too fragile board, after all.

Finally, I used the sucking pump where there was tin residual, some desoldering wick, and tons of solder flux to get a decent, if not perfect job. This is the result I achieved:

This is some proof of my personal (and long) fight:

Now should have come the easy part... quite true but not fully true.

Even with my 110W iron, soldering the GND pins of the new header was literally a nightmare! I hope this was caused by my scarce experience because it was a second difficult fight.

But it was a happy-ending fight: I can confirm I have now a fully functioning Mister FPGA built on this board and standard add-on modules, so - really - the only difference in this variant of the DE10-Nano board is the GPIO and ADC header soldering.

As a last suggestion please note the Power Supply included in the robotic kit is a 9v (or 12v I do not remember) one... so if you are going this way, please have a new 5V power supply to power the Mister. Because of distraction, I had to learn this the hard way... but it's another story...

Hope my experience can be helpful.