nRF5 action!

[NeverDie]

So, is the speed of the Cortex on an nRF5 already good enough that one can simply emulate an atsha signing component, and thus that part now completely disappears from the BOM?

[Anticimex]

@NeverDie you can run soft signing on any device. It emulates the atsha204a equally well. The performance of the MCU only affects the speed of the calculations, not the quality of the result.

[Anticimex]

@NeverDie but remember that if you use soft signing it is your own responsibility to protect the hmac key from readout by an attacker with physical access to the device.

[NeverDie]

@Anticimex said in Minimalist SAMD21 TQFP32 Pro Mini:

@NeverDie but remember that if you use soft signing it is your own responsibility to protect the hmac key from readout by an attacker with physical access to the device.

Thanks! Good to know. Speaking only for myself, I don't think I'll be losing any sleep over the prospect of an attacker gaining physical access to one of my home devices with the intent of extracting the hmac key. I'm more likely to win a lottery than have that happen--and I don't even play lotteries.

[Anticimex]

@NeverDie that is probably correct, I just feel a responsibility to inform everyone of any known weaknesses in the security infrastructure ;)

[NeverDie]

@Anticimex
I don't mean to trivialize it. For commercial applications, the atsha204a would of course make sense.

But, at least for now, it sounds likely that $2.73 will buy you the hardware for a nice little home wireless node, minus sensors and power supply. That's today's price for a NRF51822-04 MINI that NCA78 linked to above. And, of course, that price will continue to drop. Pretty cool!

[NeverDie]

Which library is most recommended for exploiting the RTC that's on an nRF52832? Likewise, what's the best library for sleeping the nRF52832? Since I have the DK, I'd like to take some current measurements while running some demo code for that. That will establish a baseline for comparing future measurements.

[NeverDie]

I just now ordered this:
https://www.sparkfun.com/products/13746?_ga=2.39569123.1141912816.1499956888-1087552930.1495048698

It's like a regular FTDI, but it can also power your project at 3.3v at up to 600ma! :) Previously I had to make my own hacked FTDI interface to do that. Ordinary 3.3v FTDI's will burn out under the load of, say, an ESP8266, or a 20db Tx power amplified nRF24L01.

[d00616]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

Which library is most recommended for exploiting the RTC that's on an nRF52832? Likewise, what's the best library for sleeping the nRF52832? Since I have the DK, I'd like to take some current measurements while running some demo code for that. That will establish a baseline for comparing future measurements.

Sleeping is implemented by hwSleep(). This function uses one RTC. If you need advanced RTC access, you have to cooperate with this RTC, because the interrupt routine must reset the state registers. On nRF51 the other RTC is used for millis(). The nRF52 has one RTC free.

[NeverDie]

In case anyone else either has, or is thinking of getting, the nRF52832 DK, it looks as though there is indeed a way to use its programmer to program an offboard nRF52832 without desoldering the nRF52832 that's on the DK. Here's the existence proof photo where an 832 DK is being used to program Sparkfun's nRF52832 breakout board over the two SW lines:

The caption reads "For faster programming, an nRF52832 Development Kit can be used to program the nRF52832 Breakout Board."
I haven't yet found the instructions on how to do it though.

[NeverDie]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

@d00616
9mmx9mm would be great. However, are you certain?

I'm convinced! I pulled this picture off the FCC website, and, indeed, it is 9x9mm:

(https://fccid.io/2AA72-PTR5628)

So, thanks for mentioning its size, or else I never would have known!

[NeverDie]

So, what's the smallest nRF52 module that also includes a 32Khz crystal? I think I might want to standardize as much as possible on a single module rather than juggle a bunch of different ones.

[d00616]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

So, what's the smallest nRF52 module that also includes a 32Khz crystal? I think I might want to standardize as much as possible on a single module rather than juggle a bunch of different ones.

What do you think about creating an table with known modules including integrated hardware, available ports and size?

I think, most small modules comes without 32kHz crystal. This is mostly an option. Maybe for the 9x9mm module. But I think the antenna is no good choice for indoor usage.

I have a lot of RedBear BLE Nano 2 (18x21mm) modules. It's complete including 32Khz crystal and a 3-13V voltage converter. With 2.54mm pins it's easy to solder.

I have asked the manufacturer(cdebyte) of the nice nRF24 and nRF52 modules if it's possible to build an module including the nRF52, an RGB LED, an button and 5V protected inputs with the layout like the popular nRF24 modules plus two optional pins (6/8 IO Ports!). I think such type of nRF52 module makes it easy to migrate to 32 Bit using existing boards or build new boards.

[NeverDie]

I just now noticed that Ebyte also has a storefront on aliexpress.
https://cdebyte.aliexpress.com/store/2077046?spm=2114.12010108.0.0.7Yid4a
For me, it's much better than ebay, because it includes free e-packet delivery to the US. So, unlike ebay, I will hopefully get their modules much sooner than September! The estimated delivery time from Ebyte if ordered through Aliexpress is 12-20 days. :)
https://www.aliexpress.com/store/product/CDEBYTE-E73-2G4M04S-BLE-4-2-5-0-long-distance-100m-2-4GHz-SMD-ARM-Core/2077046_32820692238.html?spm=2114.12010615.0.0.TZClHR

[Edit: Also, on Aliexpress, Ebyte gives a coupon for $5 off if you order >$45]

[Nca78]

@NeverDie yes noticed their shop only 2 days ago and feeling frustrated now :D
For shipment delay I wouldn't be surprised if they shipped the same way with free option and it would just be a different way to state the delay on the 2 websites...

[NeverDie]

@Nca78
We'll soon know. I ordered Ebyte products from both Ebay and Aliexpress, and I'll take note of when each order arrives.

[d00616]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

So, what's the smallest nRF52 module that also includes a 32Khz crystal? I think I might want to standardize as much as possible on a single module rather than juggle a bunch of different ones.

I have found the Raytec Modules. http://www.raytac.com/products.php?id=1
The smallest one is the MDBT42V 8,4x6,4x1,5mm with PCB antenna and 80m range in open space.

This module https://www.mtmtech.com.tw/M905.html is 6.5 ✕ 6.5 x 1.1 mm

[Nca78]

@d00616 said in Minimalist SAMD21 TQFP32 Pro Mini:

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

So, what's the smallest nRF52 module that also includes a 32Khz crystal? I think I might want to standardize as much as possible on a single module rather than juggle a bunch of different ones.

I have found the Raytec Modules. http://www.raytac.com/products.php?id=1
The smallest one is the MDBT42V 8,4x6,4x1,5mm with PCB antenna and 80m range in open space.

This module https://www.mtmtech.com.tw/M905.html is 6.5 ✕ 6.5 x 1.1 mm

M905 is impressive, but with connectors at the bottom it's impossible to hand solder...
Raytac module is what scalz used for the prototype of his "Aeos" board, pretty small but he didn't look so happy with the range.

[Terrence]

Guys, when you start using these 832 chips are you going to be programming via Bluetooth or just using the radios in some other way?

[NeverDie]

@Terrence said in Minimalist SAMD21 TQFP32 Pro Mini:

Guys, when you start using these 832 chips are you going to be programming via Bluetooth or just using the radios in some other way?

I'd like to see the work extended to include Bluetooth. Nearly everything has bluetooth these days, so leveraging that would seem to make a lot of sense. I just don't know where to start.