nRF5 action!

[NeverDie]

Just received my nRF52832 DK, and it included 5 additional nrf52832 chips in it. Wasn't even expecting that.

[NeverDie]

First impression after a quick looking it over: other than having a built-in J-Link, it looks like the DK will be of no extra benefit with respect to the mysensors nRF52832 implementation.

[Terrence]

@NeverDie why won't it be helpful?

[NeverDie]

@Terrence
Since it has a built-in J-Link, it should be helpful in programming the nrf52832 that's already soldered onto the DK. However, will it be helpful in programming an off-board nrf52832 like the adafruit board or, say, the sparkfun board? I don't know.

Maybe I haven't found the right starting point. I went to the url given on a small card in the DK, but it's mostly links to datasheets, white papers, app notes, a couple phone demo apps, software that can be downloaded, etc. I'm not finding a tutorial. Contrast that to what, for example, cypress semiconductor has for their bluetooth evaluation board, which is a whole video series of something like 50 video tutorials that walks you through from A to Z on how to use it.

[NeverDie]

I'm finally able to get some primitive sketches (such as Blink and printing to Serial) to run on the NRF52 DK using these settings:

Somewhat strangely, setting the LED pin LOW turns the LED to "ON", and setting it HIGH turns it OFF. Go figure.

[Terrence]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

Contrast that to what, for example, cypress semiconductor has

Wow, cypress is knocking it out of the park on helping us. You would think Nordic would pick up the pace.
Thanks. I will check those videos out.

[NeverDie]

OK, using the mysensors example scripts, I have the nRF52832 serving as a serial gateway, and it is receiving messages from an nRF24L01 light sensor that's running on an arduino UNO.

So, apparently, it works. :)

Anyone know whether the nRF52 DK can be used to program other nRF52832's? If not, I guess I'll have to wait for the J-Link programmer I ordered to test out that part of it and get nRF52832 to nRF52832 communication working.

[NeverDie]

Here's the really good news. I tried a very quick range test with the above configuration, and it seems to be noticeably better than with two nRF24L01's. I check the datasheets, and, indeed:

nRF24L01: -85dBm sensitivity at 1Mbps
nRF52832: -93 dBm sensitivity, 1Msps nRF mode

So, for an nRF52832, that's an 8dBm improvement in link budget just from improved sensitivity alone. i.e. more than twice the range. Nice. :)

[NeverDie]

Looks as though the nRF52840 will have the same nRF mode receive sensitivity. However, it will have a receive sensitivity of -103dBm in 125ksps BLE mode. which is huge.

[NeverDie]

It's somewhat strange that the F-antenna never caught on with the nRF24L01, which typically used some kind of meandering antenna.

However, as proven by the ESP8266's evolution, the F-antenna is superior.

So, its presence in at least some of the nRF52832 implementations (such as that pictured below) should help as well.

[gohan]

I found it on some modules from Sunfounder on red PCB but they have fake nrf24 chip and still performed bad but a little better than the other chinese clones (range 7 meters indoor instead of 5)

[NeverDie]

Presently the parts cost is higher for an nRF52832 (and surely for an nRF52840) than for an RFM69 plus an atmega328p. So, I'm struggling to justify it.

[Nca78]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

Presently the parts cost is higher for an nRF52832 (and surely for an nRF52840) than for an RFM69 plus an atmega328p. So, I'm struggling to justify it.

With only 5$ for the EBytes modules there's not much difference I think ? And for that you have a smaller size, easier soldering (compared to SMD atmega), incredibly more capable hardware that's really future proof for both MCU and radio module, lower power consumption for TX and even more for RX, ...

[NeverDie]

@Nca78
You're right. Especially after outfitting the atmega328p with an RTC, the cost is more of a wash. I think the RFM still wins on range, but maybe the 832 will be "good enough"...

[NeverDie]

I'm guessing that if I were to desolder the rFM52832 from the DK, then I could use the DK to program other chips using the SW pins by using the J-link that's part of the board.

[NeverDie]

@gohan said in Minimalist SAMD21 TQFP32 Pro Mini:

I found it on some modules from Sunfounder on red PCB but they have fake nrf24 chip and still performed bad but a little better than the other chinese clones (range 7 meters indoor instead of 5)

Interestingly, the antenna on the DK is sort-of hockey stick shaped. I guess they didn't need to compress it, since the board is so large anyway.

[Terrence]

am reading your findings with great interest. Thanks for the updates.

[d00616]

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

You're right. Especially after outfitting the atmega328p with an RTC, the cost is more of a wash. I think the RFM still wins on range, but maybe the 832 will be "good enough"...

The question is, when 832 modules are available. After announcing the nRF52832 with its preview DK, I have waited from 06/2015 to 08/2016 until modules are available for an acceptable price at aliexpress or ebay.

I think the atmega is a slow 8-bit MCU with less RAM. The limited RAM requires to transmit additional nonce packages, when signing is enabled. SoftSigning hashing is 76 times faster. A faster CPU allows to shorten the active time:

• atmega328 14000µs
• nRF51 1739µS
• ESP8266 380µS
• nRF52 183µS

The NRF24 has problems with clones, range and the limitation of packages to 32 bytes. The nRF52 allows to change the packet format to support >32 bytes packages.

At the moment sleep modes are only implemented for 328 and nRF5.

OTA updates are available for 328 and ESP8266. For nRF5 it requires to implement a boot loader. The internal flash should have enough capacity to store a simple bootloader and a firmware update.

If you plan to do a lot of writes into EEPROM the 328 has a real EEPROM. The SAMD requires an external EEPROM, the nRF5/Teensy/STM32F emulating the eeprom in Flash. The nRF5 is using the NVM driver, which allows much more writes to the emulated EEPROM. The price for NVM is some time for log cleaning after some hundreds writes.

IMHO the best MCU for creating new battery powered sensors is the nRF5 stating with a ~3€ board, if required in combination with RFM modules.

@NeverDie said in Minimalist SAMD21 TQFP32 Pro Mini:

I'm guessing that if I were to desolder the rFM52832 from the DK, then I could use the DK to program other chips using the SW pins by using the J-link that's part of the board.

I think it's simpler to use one of the ST-LINK v2 clones. The DK board should be good for development, debugging and current measurement.

[NeverDie]

@d00616 said in Minimalist SAMD21 TQFP32 Pro Mini:

I think it's simpler to use one of the ST-LINK v2 clones. The DK board should be good for development, debugging and current measurement.

What exactly do I need to do to get it work? I tried it from Windows, and failed. I seem to recall you said you got it to work from Linux after changing a definition. Would you mind showing the steps, or providing a link on how to do that?

[NeverDie]

@d00616 said in Minimalist SAMD21 TQFP32 Pro Mini:

IMHO the best MCU for creating new battery powered sensors is the nRF5 stating with a ~3€ board, if required in combination with RFM modules.

The board you linked to is an nRF51. Which do you prefer? nRF51 or nRF52?