REQ: Please work on bringing out debug pins

I placed an order to support this project !

I was looking around for circuit layout, eg Eagle Cad, or something. Understandable if not going to let that out just yet, or ever. I am willing to look it over to see if it can be squeezed to allow for debug pins or pads. I’m willing to spend extra $$$ for a multi-layered board to do so as that hardware debug is fairly critical to have for a serious board at least for my work.

It looks like PA22 and PA25 for SWDCLK and SWDIO. They can be used for GPIO and Flexcom_1 though, of course, all the wild combinations to account for and shoehorning into the feather foot print prohibits various combinations. Still, I’d personally favor maneuvering around whatever it takes to get the SWD option on a couple pins.

Thanks for the efforts !

Hello! Thanks for backing the campaign! I’ll see if there’s anything I can do to bring out the SWD pins. This is something I’ve been looking at since intial routing. There are some other important pins and power vias around some of them. I’ll take a nother look and see if there’s anything I can do to bring those out once I get back in a few days. Currently driving back home from the crowdsupply event.

I think SWD access would be a nice addition. I have just been hooking up a black magic probe (BMP) to a SAMA5D27CUB and found the boot configuration word defaults the swd pins to IOSET 1 which is PD14 and PD17. So far I have at least managed to get BMP to connect to the cpu.

I think something like this would probably be the best I can do. This design is extremely tight. Let me know if you think you can make do with just some test pads. These are pins PD14 and PD17

I think pads are all that is required.

The BMP uses SWDIO, SWCLK and ground so it would be handy to have an earth pad as well (i.e. a row of three). Other adapters, e.g. Jlink need 3V3 as well so a row of 4 pads might be even better if board space allows. Otherwise as long as it is reasonably easy to attach a wire to GND and 3V3 somewhere.

Alternatively, if there is more space, putting the pads on the bottom of the board sees OK to me.

The reset, GND, and 3.3V are all brought out to the pin headers. It was already a really tight squeeze to fit those 2 pads and required scooting a few parts on the bottom around a little. Hopefully this is good enough :smiley:

I think that will be just fine.

There are other Adafruit feathers that just have two pads (SWDIO SWCLK) for debug.

Its a really cool board, I hope the campagn is a raging success!


That is absolutely better than nothing :slight_smile:

Some Adafruit boards have pads on the bottom for SWD. I’ve ruined a few while soldering because the traces are so thin they rise off the board with even minimal heat on the pads in some cases…super delicate. I’ve often wondered if I can convince them to extend the processor boards enough to allow for a typical 10 pin header while keeping the same regular pin pattern for wing compatibility.

I figured by putting the via right in the pad, it would help keep the pad from coming off. :smiley:

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