RF24 works between 2 UNOs, not with a Yun

Projects Networking, Protocols, and Devices
1

Hi,

I have the PingPair example solidly running on two UNOs, did quite some testing around the house, did one mild tweaking (lower transmission rate) and everything works fine (some 20 ms round time delays, and transmission works 100% between the two intended locations).

Then I replaced the "Ping" UNO with a Yun, and as a result

  • the script doesn't show anymore the header information (I could live with that)
  • the received back value is (instead of the constantly changing sent millis value) always 4294967295
  • the delay value then of course is the original millis value

I've tried it with two different Yuns, just to be sure, same result (exactly the PingPair sketch, exactly the wiring that works on the UNOs).

Output of the Yun (Ping):
Now sending 9051...ok...Got response 4294967295, round-trip delay: 9054
Now sending 10054...ok...Got response 4294967295, round-trip delay: 10056
Now sending 11057...ok...Got response 4294967295, round-trip delay: 11060

While the UNO is still waiting to pong back (no serial output after the header).

When I switch roles, make the UNO the Ping and the Yun the Pong...

Output of the UNO (Ping):
Now sending 90...failed.
Failed, response timed out.
Now sending 1370...failed.
Failed, response timed out.
Now sending 2647...failed.

Output of the Yun (Pong):
Got payload 4294967295...Sent response.
Got payload 4294967295...Sent response.
Got payload 4294967295...Sent response.
Got payload 4294967295...Sent response.
Got payload 4294967295...Sent response.
Got payload 4294967295...Sent response.

Any ideas?

Thanks!

2

PS: When I unplug the nRF module from the Yun, I get exactly the same serial output. Which could indicate that when I plug it in like for a UNO, it's like not plugging it in at all.

3

ok, I found it.

MISO, MOSI and SCK are only available on the ISCP header. This is documented for the Yun, but since all nRF24* tutorials on the web don't touch the Yun, I missed this piece.

attach to a Yun:

ICSP:

YUN (readable - the header is on the right side of the board)!

MISO (violet) x x +5V
SCK (green) x x MOSI (blue)
RST x X GND

I hope I can now use a Yun as internet gateway / webserver, and then do the IoT stuff via nRF24.