NanoFury Project - Open Source Design

[MacEntyre]

I register my interest in a possibly upcoming NF6 DIY kit.
 

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[mikerbiker6]

I have some questions about the NF1 (0.7). (yellowjacket)

According to the parts list, CF1.8-1 is a 100nF capacitor.




But it looks nothing like the other 100nF capacitors on the schematics.



Also, what are those small gray circles on the left.
And what is the purpose of the contacts right of the bitfury chip, no components are going to be placed there.

thanks.

[vs3]

According to the parts list, CF1.8-1 is a 100nF capacitor.
https://i.imgur.com/7dx862b.png
But it looks nothing like the other 100nF capacitors on the schematics.
https://i.imgur.com/bgr3zzv.png

The footprint is supposed to be 0603 and at various points I was experimenting also with 0805 - it is possible that I may have forgotten to switch the package back to 0603. Either way - the two are very close and 0603 will work with either one.

Also, the component label isn't perfectly placed and that might be adding to the confusion.

Also, what are those small gray circles on the left.

gray circles are vias. I think I left them visible on some of the assembly drawing pictures so that you can identify a bit more easily which component and track goes where.

And what is the purpose of the contacts right of the bitfury chip, no components are going to be placed there.

Those are test pins (or pads). They're there for testing purposes. And they're also very handy if you want to add more chips to the chain as they expose the OUTMOSI/OUTMISO/OUTSCK pins (as well as OUTCLK if you want to check chip's internal oscillator frequency with some external tools).

[TheRealSteve]

I have some questions about the NF1 (0.7). (yellowjacket)
According to the parts list, CF1.8-1 is a 100nF capacitor.

Parts list might be mistaken - according to the schematic, it should be a 22uF capacitor (same as e.g C21 close to it).

Also, what are those small gray circles on the left.

They're vias - small plated through (meaning there's copper around the inside) holes that connect the copper on the top layer to copper on the bottom layer.  You usually place a bunch of these around - you can see more near C1, by the NanoFury text, etc.

And what is the purpose of the contacts right of the bitfury chip, no components are going to be placed there.

Those are P1 through P6 P7 in the schematic - they're just test points, e.g. for checking performance and behavior with an oscilloscope or logical analyzer

Edit: What he said!

[mikerbiker6]

Thanks guys,

The footprint is supposed to be 0603 and at various points I was experimenting also with 0805 - it is possible that I may have forgotten to switch the package back to 0603. Either way - the two are very close and 0603 will work with either one.

So suppose I had a 100nF cap. Could I place that in CF1.8 instead of a 22uF one?(or the other way around)
That is a big difference, won't you totally blow that one up.


I have one more question, in the red square is a very big patch of conduction material(with the holes), should you fully solder that or not,
since the chip already has connector pins?

[TheRealSteve]

So suppose I had a 100nF cap. Could I place that in CF1.8 instead of a 22uF one?(or the other way around)
That is a big difference, won't you totally blow that one up.

I'll leave that one for vs3, given the conflict between schematic and parts list

I have one more question, in the red square is a very big patch of conduction material(with the holes), should you fully solder that or not, since the chip already has connector pins?

Those holes are for thermal transport (from the chip, through the board, to the other side, and to the heat spreader/heat sink.  You can fill them with thermally conductive material, that should actually improve thermal transport a little bit.  Filled and plated over boards are relatively expensive, so you wouldn't see that happening very often (might see it in e.g. BGA designs where you've got via-in-pad nastiness).

[vs3]

Thanks guys,

The footprint is supposed to be 0603 and at various points I was experimenting also with 0805 - it is possible that I may have forgotten to switch the package back to 0603. Either way - the two are very close and 0603 will work with either one.

So suppose I had a 100nF cap. Could I place that in CF1.8 instead of a 22uF one?(or the other way around)
That is a big difference, won't you totally blow that one up.

Both CF8 and CF1.8-1 are in parallel, so it doesn't really matter which goes where. They now have the same pads, so you can put either one at either location.
From a practical point you may want to put the 100nF (CF1.8-1) closer to the bitfury chip as the capacitor is a bit smaller and easier to place there. And as for CF8 - since the bitfury chip draws very little current you can even experiment by not placing it at all. I've experimented with various values - 1/4.7/10/22uF and things are fine with any one of them.
Just make sure to put at least one of the two capacitors - the 1.8V regulator may start misbehaving if both are missing.

Aside from that - I'm not sure where you got the BOM from - on my schematic C8 is 10uF. (And CF1.8-1 is incorrectly 0805 on both the schematic and PCB - it should've been 0603).


As for the big pad - TheRealSteve already mostly covered it:

I have one more question, in the red square is a very big patch of conduction material(with the holes), should you fully solder that or not, since the chip already has connector pins?

Those holes are for thermal transport (from the chip, through the board, to the other side, and to the heat spreader/heat sink.  You can fill them with thermally conductive material, that should actually improve thermal transport a little bit.  Filled and plated over boards are relatively expensive, so you wouldn't see that happening very often (might see it in e.g. BGA designs where you've got via-in-pad nastiness).

Most of the vias would get at least partially filled with solder during the process - which causes also some solder to seep to the back side resulting in a bit uneven surface there - keep it in mind when selecting the thermal pad!

Below is an image of how things would look when you overlay the solder mask and solder paste:

[vs3]

Out of curiosity - where did you get that board from?

From my recollection those boards were black ...

[TheRealSteve]

Out of curiosity - where did you get that board from?

From my recollection those boards were black ...

http://shop.bitgtr.com/yellowjacket-pcb-diy-educational-edition/

He started selling some bare boards

[mikerbiker6]

Out of curiosity - where did you get that board from?

From my recollection those boards were black ...

http://shop.bitgtr.com/yellowjacket-pcb-diy-educational-edition/

He started selling some bare boards

Yes that is where I got the boards and the BOM from.

[mikerbiker6]

Ok, the soldering took some time.
The main problem was that the solder paste didn't wanna let go of the tip of the syringe.
Therefore it was hard to precisely solder everything.

Here are some pictures after heating.
http://imgur.com/a/5jSxL

The usb plug is not soldered yet. but that is not such a problem.
The problem is the bitfury chip, some bridges have formed.
What do you think is best, use a soldering iron to remove the bridges?

[TheRealSteve]

The problem is the bitfury chip, some bridges have formed.
What do you think is best, use a soldering iron to remove the bridges?

Solder wick, or re-do (chipquick is some nice stuff for that).

http://www.theledart.com/blog/archives/1301

[mikerbiker6]

Solder wick, or re-do (chipquick is some nice stuff for that).

http://www.theledart.com/blog/archives/1301

Thanks, will add that to my bookmarks.
Nanofury bookmarks now totalling over 100 haha. ( all those tutorial videos lol)

[TheRealSteve]

Thanks, will add that to my bookmarks.

You should definitely bookmark the source of the video - http://curiousinventor.com/ - there's plenty more (de)soldering tutorials in there, and they're a Bitcoin enthusiast as well.

[vs3]

The problem is the bitfury chip, some bridges have formed.
What do you think is best, use a soldering iron to remove the bridges?

Solder wick, or re-do (chipquick is some nice stuff for that).

http://www.theledart.com/blog/archives/1301

+1 :-)

Solder wick is your best friend!
And an old fashion toaster oven might be your second best one


Also take a look at this video:
https://www.youtube.com/watch?v=c_Qt5CtUlqY
(the interesting part starts after 3:30)

Also, I've been using SMT stencils for majority of my work and that's how I've been making my prototypes.
Here is how I did mine: http://imgur.com/a/5hXU4

[intron]

Solder wick is your best friend!
--
Cohesion is your better friend;)

[mikerbiker6]

I finished one nanofury.
But both my pc and rspi are not seeing the device. Also the led is not on while plugged in.
Is this a driver issue, or probably a malfunctioning component?(or something else).

[vs3]

I finished one nanofury.
But both my pc and rspi are not seeing the device. Also the led is not on while plugged in.
Is this a driver issue, or probably a malfunctioning component?(or something else).

Start it by one step at a time.
1. Plug it into the PC (I'm presuming running Windows). It should beep and say a new HID device has been found. You should also be able to see the HID device in Device Manager. (if that doesn't happen then most likely your MCP2210 isn't working - check voltages, shorts, oscillations on the crystal pin, etc)

2. Run the nf1_init program. (source: https://github.com/nanofury/NanoFury_Init ) There are two things you're looking to do with it:
2a - it should recognize the device and print the serial number and Product String. The Product String is important.
2b - run the program again with fixID parameter and it will change the ProductString to "NanoFury NF1 xxxx" - the NanoFury one is mandatory for bfgminer to recognize the device. NF1 is optional and is used by other mining software, so make sure to put both (if you're customizing the string). A few pages ago there were links to other programs that can be used to change the string.

Also, at that step the nf1_init program while testing the device will make the LED blink.

If you make it that far - then your device should be good to go.

3. Run BFGMINER and experiment with the osc6 speed. If you haven't put any heatsink then don't push it way beyond 40-45. If you have an infrared thermometer you can check temperature - try to keep it below 75C. If it gets beyond 85C it will start misbehaving and you'll start seeing tons of errors.

If BFGMINER recognizes the device and can communicate with the MCP2210 but prints lots of init errors - that's an indication that there is something wrong with the communication between it and the bitfury chip. Check the resistors between the two, check for shorts, check voltages, etc

You can use the nf1_init program with the test parameter to get the device to turn on the various voltages and measure what's going on.


Good luck!

[mikerbiker6]

Well it is not in devices in windows,
But I Noticed a difference in your work and mine.
I did not solder these pads since there is not going to be placed a component anyway.
I don't see a point in soldering those, the are already conducting.

Notice the red circles:

[vs3]

But I Noticed a difference in your work and mine.
I did not solder these pads since there is not going to be placed a component anyway.
I don't see a point in soldering those, the are already conducting.

Notice the red circles:

that is correct - there are two sets of pads for the MCP2210 depending on which package you get. You should only use one of them and leave the other untouched.