MicroPython Forum

Posted: **Thu Jun 11, 2020 4:11 pm**

Hi,

I know that similar questions were asked before, but after browsing quite a lot of threads on the forum, I couldn't find exactly what I need. In short, I would like to find a board that matches all these conditions:

- cheap (< 10 €)
- has bluetooth
- small (something like 20x30 max)
- has 2.54 mm pins (so it can be soldered directly on a perfboard)
- has at least one ADC
- can run micropython, of course

The bare ESP32 could match this description, but the pins are very close together. Trying to solder it on/to a perfboard inevitably means soldering it to an adapter, and then the overall bundle isn't small anymore.

I was able to find something that matches my requirements (I think) here: https://www.aliexpress.com/item/3284765 ... hweb201603_

And I know that micropyhton runs on the NRF52.

WHat do you guys think? Do you have any other board in mind that matches my requirements?

Cheers

Posted: **Sun Jul 05, 2020 4:04 pm**

Hi,
I would go with the Ebyte E73-2G4M04S1B nRF52832, easy to solder, comes with an external low power crystal and cheaper. It has only 512KB flash but you can run most of you python code on it. Ebyte's dev board E73-TBB nRF52832 is probably what you're looking for.

Regards,

Posted: **Mon Oct 05, 2020 11:33 pm**

If you're interested in using the EByte E73-TBB, have a look at these three:
https://medium.com/@ly.lee/bluetooth-me ... 823407c471
https://medium.com/@ly.lee/coding-nrf52 ... 21bcba6004
https://ssihla.wordpress.com/2019/07/23 ... ese-board/

Posted: **Thu Oct 08, 2020 10:59 am**

Great, Its really very useful medium links.

Posted: **Sat Dec 05, 2020 6:53 am**

EByte E73-TBB

Was pretty easy to flash MicroPython to it!

EByte E73-TBB: https://www.aliexpress.com/item/4000516424563.html
J-Link clone: https://www.aliexpress.com/item/4001335080402.html

Install command line tools (on macOS):

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https://github.com/ARMmbed/homebrew-formulae
brew tap ArmMbed/homebrew-formulae
brew install arm-none-eabi-gcc
brew install homebrew/cask-drivers/nordic-nrf-command-line-tools

Compile and flash:
* Clone lastest micropython.
* Grab the e73 board def from: https://github.com/micropython/micropython/pull/5055
* Save the files in a new dir: ports/nrf/boards/e73
* Connect the E73-TBB to J-link (you can't use the E73-TBB onboard USB yet)
* make, deploy (,unlock, deploy)

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cd microython
make -C mpy-cross
cd ports/nrf
make submodules
make BOARD=e73
make BOARD=e73 deploy

If you hit this error, you need to disable the flash protection:

Code: Select all

ERROR: The operation attempted is unavailable due to readback protection in
ERROR: your device. Please use --recover to unlock the device.

Run this to unlock:

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$ nrfjprog --recover -f nrf52

Recovering device. This operation might take 30s.
Erasing user code and UICR flash areas.

Then try to deploy again:

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$ make BOARD=e73 deploy

Use make V=1 or set BUILD_VERBOSE in your environment to increase build verbosity.
nrfjprog --program build-e73/firmware.hex --sectorerase -f nrf52
Parsing hex file.
Erasing page at address 0x0.
Erasing page at address 0x1000.
Erasing page at address 0x2000.
....
Applying system reset.
Checking that the area to write is not protected.
Programming device.
nrfjprog --reset -f nrf52
Applying system reset.
Run.

Flashing complete. You can now try MicroPython REPL over USB.
* Unplug the j-link debugger.
* Connect to the E73-TBB onboard USB.

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$ screen /dev/tty.usbserial-1420 115200

MPY: soft reboot
MicroPython v1.13-221-gc8b055717 on 2020-12-05; E73-Demo with NRF52832
Type "help()" for more information.

/dev/tty.usbserial-1420 is my 2nd USB-C port on my MacBook Pro.
ls /dev/tty.* to see what yours is.

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