nRF5 action!

[NeverDie]

I finished the first pass, and it looks as though everything will fit:

A bit more work to do, but this is the approximate form it would take.

[Terrence]

@NeverDie NRF or RFM?

[NeverDie]

@Terrence said in Minimalist SAMD21 TQFP32 Pro Mini:

@NeverDie NRF or RFM?

Neither. This is just the MCU. If I can get it to run blink, then as a next step I'll add a radio.

It's basically a subset of the sparkfun board, but in a different form factor, with a different USB, and all in 2-layer rather than 4-layer. This will be my first ARM board, so I'm just trying to keep it as simple as possible. The razzmatazz can come later.

[NeverDie]

I polished up the USB and re-positioned the headers so they'd fit on a breadboard:

The irony is: after having done all that, I can now more clearly see that it's just not a very efficient form factor. I think for future versions I'll make it not so narrow.

[Terrence]

@NeverDie It is an interesting exploration. It seems you don't see it until you get there.

[NeverDie]

I just now sent this to OSH Park:

to see whether or not it works. I still don't know how many uH are the value for the one inductor that Sparkfun used though. Any guesses?

[Nca78]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

I still don't know how many uH are the value for the one inductor that Sparkfun used though. Any guesses?

I see no inductor on Sparkfun's schematic ? Only a 30 Ohm ferrite bead.

[NeverDie]

@Nca78

Thanks! I guessing this part should do the business then: https://www.digikey.com/product-detail/en/wurth-electronics-inc/742792601/732-4659-1-ND/4310409

[NeverDie]

Argh. For only a little more than what I paid for the Sparkfun SamD21, I couldn't have gotten the same MCU with an RFM69HCW! And it's already on a 2-layer board, not a 4-layer board:
https://www.adafruit.com/product/3176
https://www.amazon.com/Adafruit-Feather-RFM69HCW-Packet-Radio/dp/B01K62LWBC/ref=sr_1_1?ie=UTF8&qid=1497022595&sr=8-1&keywords=Adafruit+Feather+M0+RFM69HCW

<insert facepalm icon> I should have started with that instead, because that's already probably close to what I'll end up with.

[Nca78]

It's a very good price. If you do it yourself you have a 3$ MCU, 3$+ radio, 1$ PCB and a few US$ for other components (like lipo charger). Leaving only 10$ left for assembly but if you do it yourself you need a lot of time even with a stencil.

[NeverDie]

And believe it or not, the LoRa version can be had for as little as $15.99 each with Prime delivery:
https://www.amazon.com/gp/product/B01LHTU14W/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Yeah, at that price I think this becomes a buy, not build, decision.

[Nca78]

@NeverDie be careful this is a "featherwing" = "shield" style board that you add to the basic "feather" board.
So you need 20$ for feather board + 16$ for radio ... not so cheap anymore ;)

[scalz]

if i remember well, the adafruit board is SAMD21G.

Here another example, sort of feather i made a while for testing SAMD21E. The same it's rechargeable, and I added some features like a rgb led, sma connector for RFM69/95, flash, signing, MYSX etc..

mounted with a weather extension board i made. If there is an interest, i can clean a bit my files and upload it, it's working well ;)

[Nca78]

@scalz said in Minimalist SAMD21 TQFP32 Pro Mini:

If there is an interest

There's interest here :D

[NeverDie]

@scalz
I'm very interested too. It probably beats my bumbling attempts at making a Sam21DE18, and if it's already working well, what's not to like?

[Terrence]

@NeverDie I love the Feather boards. Currently working with the RFM69 feather. Build in battery connector/charger is very nice to have.

[scalz]

@NeverDie @Nca78 oki noted!
@Terrence yeah, agree too. i have assembled one for testing as it was new and not available. Unfortunately, regarding Mysensors use, there are no flash for ota (in case for future), no signing, no eeprom for routing table (atsam has no eeprom, only emulation if i remember), no sma connector ...

[NeverDie]

@Terrence said in Minimalist SAMD21 TQFP32 Pro Mini:

@NeverDie I love the Feather boards. Currently working with the RFM69 feather. Build in battery connector/charger is very nice to have.

Good to hear! :) I ordered one today (after my posting above). There's a good chance I'll receive it on Sunday. I look forward to trying it out.

[Terrence]

@scalz >>Unfortunately, regarding Mysensors use, there are no flash for ota (in case for future), no signing, no eeprom for routing table in mysensors, no sma connector ...

Well so one of you brilliant guys will come up with a FeatherWing that will add all of that functionality right? :thumbsup:

[scalz]

@Terrence and no usb goodies for protection. woops can't be added on an external board :) I'm kidding, well, i let others make this featherwing, enough busy on my side ;)