nano CUL not working

[jaccol]

I bought a nano CUL, but after loading this software nothing happens.

I suspect that the pinout of the device is different from the pinout that is currently supported.

The device I have is this one: https://www.smart-home-komponente.de/nano-cul/nano-cul-868-extern/
I guess - on inspection - that the cc1101 is connected to 3.3V, while there is only a board definition for a atmega328p w/ 5V.

I followed the instructions from the README, pointed the arduino UI to evofw3.ino and pushed 'Upload'. There were no errors in that step.

From here I expected the 'Serial Monitor' to show some output. nothing. I tried giving commands like !F, V, !V, etc but there never was any response from the Arduino.

Can anyone give me some pointers on how to proceed debugging?

Thanks,

Jacco

[ghoti57]

The 5v is the power to the processor, not the cc1101.

It's usb powered so probably 5v. You just need to make sure there's not a regulator reducing the cpu input power to 3.3v

Might be worth asking Smart Home Komponente about schematics

[ghoti57]

There are alternative build options for the 328 that are different pinouts to the cc1101

[jaccol]

There is a pdf detailing which pins are used:
https://www.smart-home-komponente.de/support/aufbauanleitungen/

But if I read your board definition, the main question is the order of INT0/INT1
could I try a 'pro' layout in stead of a 'nano' or are there other differences between those?

[ghoti57]

That's the only difference between the pro and the nano

[benjaminvdb]

@jaccol Were you able to get the firmware working? I'm considering to purchase the same USB dongle, since the one referenced in this repository is out-of-stock.

[jaccol]

I have not been able to get it to work, but I also did not spend much time on it, busy with other projects. I won't have physical access to the device for the next three weeks ...

[dennisvbussel]

FYI i build a custom dongles using the Arduino Pro Micro 3.3V 8Mhz and a 868 radio. It only required a minor rework.

My tip is double check your SPI connection. Mine had the CS pin routed to the led. Unlikely though that de nanocul usb you bought has this issue.

[ghoti57]

@dennisvbussel

You appear to have moved the connection for the SPI CS pin,
What build options did you use to build?

The standard options available for
Atmega32u4 (3V3 8MHz) , pinout Pro Micro
should have compiled the firmware to use pin 18 ( Port B pin 6) on your board.

I suspect you used the SHA atmega32u4 pinout option which does attempt to use Port B Pin 0 for CS.
This pin does not appear on an edge connector which is why you appeared to need to solder on a wire.

[ghoti57]

@dennisvbussel

You might want to look at this picture.

I found a lot of variation in the antennas I used early on.
I found the ones that had a much longer effective length were not working as well.

The one at the top was by far the best, so I experimented with trimming one of the longer ones and improved it to the same as the top one.

You can see that I progressively trimmed more away each time before getting the best result.

The length of the wire in the top antenna was 137mm, By the time I finished the bottom one it was about 143mm.
The antenna in your picture looks significantly longer.

When you calculate the length (L) you need to take into account the coil diameter(D), wire diameter(d), number of coils(n) and stub length(l).

L = l + n x pi x ( D - d )

You might want to play with the length of your antenna.

For reference, the antenna in this image works very well.
https://www.amazon.co.uk/dp/B07NJV1F6F/
You can see it's very similar to the top one above

[dennisvbussel]

Yes indeed @ghoti57, I used the default build. Probably it would have been easier to just update te IO config however, now I get a cool looking led blink whenever the SPI bus is addressed :).

Regarding the antenna, I bought and assembled it as-is and so far it is working perfectly within my entire house :).

Antenna theory is cool but can be tricky to tune without proper equipment.

[ghoti57]

Used incorrect configuration resulting in need to patch connections