nRF5 action!

[Toyman]

Just curious design consideration, based on my question to Nordic:

https://devzone.nordicsemi.com/f/nordic-q-a/33448/led-power

LED consumption will not exceed 0.5ma if the pin is configured as s0s1

[NeverDie]

@toyman Maybe that's enough to light a subset of the pixels on the display?

In theory these nRF52832 BLE are OTA re-programmable. If someone left the door open for that, then you wouldn't have to crack the case or fight with the glue. Well, maybe someday...

[Toyman]

@neverdie I was thinking about that, but that's not gonna work. Why? The bootloader that accepts OTA has a private key. The key in the software should match the key.

[NeverDie]

@toyman Would this work? Buy two. Sacrifice the first so that you can image the firmware on the chip and extract the password. Use that password to unlock the OTA firmware update for the second one.

Or, maybe it's the universal bluetooth password: 1234. Maybe try that first. ;)

[scalz]

afaik mysensors nrf52 isn't working with softdevice yet (same as your 'bootloader' here). there might be some conflicts with nrf52 resources (timers etc.). so you may need to open it for reprogramming.

[alowhum]

For me losing Bluetooth would be a feature: it makes you less likely to be tracked while in stores / smart cities.

[alowhum]

I turned a ST-Link v2 into a Black Magic Probe using this guide.

The Black Magic Probe creates two virtual serial ports. One to program over, and another one. Can that second one be used to listen to Serial output from the NRF52? If so, how can that be set up?

[NeverDie]

@alowhum Doesn't answer your question, but I use just regular FTDI to listen to the serial output from the nRF5. So, there's always that for you to fall back on.

[nagelc]

@alowhum I'm using a BMP that I made from a STM32 Blue Pill. The Serial works just fine.
Set a TX pin on your NRF5 in the MyBoardNFR5.h file. Connect it to the RX pin on your BMP. The default pins are TX (PA.2) and RX (PA.3). So if you connect PA.3 on your programmer to the TX pin you select on the NRF5, you should have what you need.
To program, select the lower number serial port.
To see serial output, select the higher number serial port for your serial monitor.

[alowhum]

@nagelc I am using a ST-Link V2 that I turned into a BMP. So i don't have a RX pin on that. But I do have these pins left:

• RST
• SWIM

So you suppose any of these two pins are now RX?

[NeverDie]

@toyman Looks like a DIY watch, using one of the very small nRF52 modules and a small OLED screen (or maybe ePaper?) would be fairly easy to design and put together.
https://www.aliexpress.com/item/Free-shipping-Latest-Big-time-wearable-devices-DIY-electronic-watch-programmable-watch-FOR-ARDUINO/32309696848.html?spm=2114.search0104.3.43.6855283fBpRmHN&ws_ab_test=searchweb0_0,searchweb201602_5_10152_10065_10151_5711320_10344_10068_10130_10324_10342_10547_10325_10343_10546_10340_10341_10548_10698_10545_10697_10696_10084_5722520_10083_10618_10307_5711220_10059_5722620_5722920_308_5722720_5722820_100031_10103_441_10624_10623_10622_10621_10620-10152,searchweb201603_25,ppcSwitch_5&algo_expid=e4147df1-7362-4700-8575-4d5fa986cd9a-6&algo_pvid=e4147df1-7362-4700-8575-4d5fa986cd9a&transAbTest=ae803_1&priceBeautifyAB=0

Making it aesthetically pleasing is probably much harder! Still, maybe a DIY bridge would tide you over until a more proper watch is available for conversion. Interestingly, it looks like they made their case from stacked pieces of laser cut acrylic.

Unfortunately, theirs is impractically large:

[nagelc]

@alowhum Reset seems unlikely. Maybe SWIM. You could try it.
If you can follow the trace back to the microprocessor, then you could figure out which pin it is. Then you could change to that pin in the BMP files, recompile, reload . . .. . Not sure it's worth all that experimentation when you can just use an FTDI as @NeverDie does.

[gohan]

Is this an alternative programmer or is it STM32 only? https://www.aliexpress.com/store/product/CJMCU-JLINK-Support-for-SWD-s-JLINK-Simplified-Edition-Supports-STM32-SWD-Debugging-3-Wire/1245924_32792177272.html

[mfalkvidd]

@gohan J-Link is in the list of supported programmers at https://github.com/sandeepmistry/arduino-nRF5 so it should work

[Toyman]

@alowhum just buy a real Blue Pill (around $2) and convert it into BMP.
Then you''ll get both a programmer and an USB-serial that you can use to get data from NRF52 UART

[Nca78]

@toyman said in nRF5 Bluetooth action!:

@alowhum just buy a real Blue Pill (around $2) and convert it into BMP.
Then you''ll get both a programmer and an USB-serial that you can use to get data from NRF52 UART

Thank you for this idea, I didn't receive my STM32 (got lost somewhere in transit) but I have 2 unused blue pills, I'll try that tomorrow.
"Conversion" process is easy to find: https://medium.com/@paramaggarwal/converting-an-stm32f103-board-to-a-black-magic-probe-c013cf2cc38c

[NeverDie]

Is the main (only?) advantage of the BMP that you have a single USB connection from your PC to your project instead of two (e.g. J-link plus an FTDI)? Or is there more to it that that?

[Toyman]

@nca78 I used exactly this guide. Works like a charm.

[Toyman]

@neverdie for us - yes. For other folks, I think the advantage is the number of targets it supports and the license. Equivalent Segger costs hundreds of $
BTW, Sandeep added BMP support into his core after I raised the issue :-)

[Toyman]

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