nrf52840 pi hat

RE: nrf52840 pi hat

Andreas — Thu, 04 Apr 2019 12:01:43 GMT

Hi,

Thanks for exporting gerbers. The footprint looks better now, you can probably proceed with placing the components. Again, I strongly recommend that you replicate the reference design as closely as possible, especially the RF part. Deviations to distances between components, pins, pads, ground pour etc. all affect the performance to some extent, by being 'nitpicky' you increase the likelihood that you get a well performing board and thus do not have to do another spin or make any janky fixes to make it better.

Best regards,

Andreas

RE: nrf52840 pi hat

sentinel_infinitus — Tue, 02 Apr 2019 18:00:06 GMT

hi Andreas

i did fix the part so that there were no vias under any pads

also i have created the basic hat and even exported it's gerber files there in the hat\basic hat folder

would you mind taking a look at it to see if the pcb is good

something to make note of is hat you can do micro vias under pads in kicad by setting up a micro via off to the side and dragging it under the pad you want it under if you get a question about it in the future

RE: nrf52840 pi hat

Andreas — Thu, 28 Mar 2019 12:45:51 GMT

Hi,

This looks quite good. As you say, the reference design uses blind/micro vias in the inner-row pins. This is to make sure the SoC has good ground in that the center pad is connected to a solid plane in either inner or bottom layers. By using through hole vias this will no longer be the case, the vias wil break up the ground plane which might keep certain sensitive parts in the SoC from operating as specified.

There are some ways to workaround this, by not using all the inner-row pins there will be better grounding overall. In addition there are some pins that you easily can route outside through the top layer. The ANT pin and the VSS_PA pin should also not have vias in them.

I have also seen examples of designs where the inner-row pins have been routed out in the top layer between the pads of the outer-row pins. This obviously will depend on the capabilities of your PCB supplier and EMS. You might also have to make the pads of the outer-row pins a little smaller.

Best regards,

Andras

RE: nrf52840 pi hat

sentinel_infinitus — Thu, 28 Mar 2019 04:41:01 GMT

hi Andreas

unfortunately i was using library's that i found online but they were missing pads on the footprint/schematic

that being said i have taken the time to learn how to make parts and have created the part to the best of my ability (it came out as good as i thought it would)

if you want to take a look at the part in the editor the same library adding instructions i had before should work as long as you use the location of the part i created

the part is in the parts folder under the folder [sentinel]

here is what i have though

here is what the footprint looks like

this is the settings for the red pads

this is the clearances of the red pads

the yellow pad settings (please note they are through hole because that was the only way i could get them go to other layers)

yellow pad clearance

i know it does not follow the aqf73 guideline too well but it was the best i could do based on my limited experience with making kicad parts

it would be nice if in the future nordic made kicad parts available in the future or if nordic want to make this part available to people i would not mind

RE: nrf52840 pi hat

Andreas — Tue, 26 Mar 2019 09:11:32 GMT

Hi,

Unfortunately we do not have any experience with KiCad. I did a quick web search though, seems you should be able to find some nRF52840 libraries which you might be able to use (if this is not what you have done already).

Best regards,

Andreas

RE: nrf52840 pi hat

sentinel_infinitus — Mon, 25 Mar 2019 19:18:11 GMT

well i started to impliment the new documentaion and i have learned the part i am using does not have all the pins on it so it looks like i will have to learn how to make custom parts for kicad

RE: nrf52840 pi hat

Andreas — Wed, 20 Mar 2019 08:41:30 GMT

Hi,

OK no problem, I can look over it once you have redone it. As mentioned though you should replicate the reference layout as closely as possible. There is no need to reinvent the wheel, you will just risk inventing new bugs or ways to degrade the RF power.

You can find the reference layout here: https://www.nordicsemi.com/Products/Low-power-short-range-wireless/nRF52840

Best regards,

Andreas

RE: nrf52840 pi hat

sentinel_infinitus — Wed, 20 Mar 2019 03:11:55 GMT

I plan on redoing part of it anyway but at the moment I can't my pc has been disconnected for the moment and I have ordered a few upgrade parts that have shipped today

RE: nrf52840 pi hat

Andreas — Mon, 18 Mar 2019 13:40:19 GMT

Hi,

I updated my KiCad application, that seemed to do the trick. Please verify that what I am seeing is correct though:

This is not good, and probably will not work at all. I recommend that you take a look at our reference layout, there are pdf files which you can look at. Rotate the nRF 90 degrees clockwise so that the ANT pin points towards the RF components and place components similar to the reference layout. You have loads of available space, there is no reason to place components all over the place.

When the ref. layout is replicated you can route GPIOs to targets on their respective side. If any pins are to be connected to anything on the opposite side of the chip it is better to see if you can re-assign the trace to a GPIO on the side which points towards the target, instead of routing a bunch of traces around the chip.

Lastly, add a ground pour in the outer layers and connect all component ground pads directly to it, no wire grounding.

Best regards,

Andreas

RE: nrf52840 pi hat

sentinel_infinitus — Fri, 15 Mar 2019 22:43:43 GMT

chances are you don't have the parts added and thats why you can't see them

all the parts in use are in the parts folder most of them you have to add via mousers part loader it will create a library that you will have to add manually

there is one part that is not added via part loader for that one you just manually add it

to add parts to the schematic view open the schematic view

preferences>manage symbol library>browse library

ex: nrf52840-qiaa {pihatfolder}/kicad-library-master/kicad-library-master/schema-components/nrf52840-qiaa.lib

ex:[SamacSys_Parts aka mouser parts lib] C:/libloader/SamacSys_Parts.lib this is where mine is

to add the footprints open footprint library editor

preferences>manage symbol library>browse library

ex:[SamacSys_Parts again the mouser parts] C:/libloader/SamacSys_Parts.mod

ex: RuuviTag /nrf52840 pi sheild/kicad-library-master/kicad-library-master/RuuviTag.pretty [please note this one is a folder]

also there is a hat.pdf it's the schematic in pdf format this is what i assume you are referencing in the quoted section
{quote}

[For some reason I am not able to view the design layout, probably due to my own KiCad incompetence. Are you able to export gerbers or something else?[

RE: nrf52840 pi hat

Andreas — Fri, 15 Mar 2019 12:56:59 GMT

Hi,

DEC4 must be connected to DEC6, this was changed after v0.5 of the OPS was released, you might want to reference documentation which is up to date. https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF52840/latest/keyfeatures_html5

For some reason I am not able to view the design layout, probably due to my own KiCad incompetence. Are you able to export gerbers or something else?

Best regards,

Andreas

RE: nrf52840 pi hat

sentinel_infinitus — Tue, 12 Mar 2019 13:39:48 GMT

hi kenneith

it gives me more time to try and route the pcb as it currently is and try and refine it's design

RE: nrf52840 pi hat

Kenneth — Tue, 12 Mar 2019 12:25:39 GMT

Hello,

This week unfortunately all of the main hardware engineers are on technical training, they will look at your case when they are back next week.

Sorry for the delay.

Best regards,
Kenneth