nRF24L01+ addressing issues

RE: nRF24L01+ addressing issues

ovrebekk — Fri, 03 Mar 2017 08:09:04 GMT

Those addresses look much better. In our older address generation guide lines (for the nRF24L01) we recommended to avoid repeating the same byte over and over, but if you don't notice any higher packet loss it's probably fine.

RE: nRF24L01+ addressing issues

gacekky1 — Fri, 24 Feb 2017 17:36:32 GMT

Hmmm... That's unfortunate. But thank you for replicating the test! Now I can say for sure to avoid these addresses.

I have each TX Pipe set up like so: Default for pairing: 0xD2, 0xD2, 0xD2, 0xD2, 0xD2 PIPE0: 0x0A, 0x01, 0x01, 0x01, 0x01 PIPE1: 0x0B, 0x01, 0x01, 0x01, 0x01 PIPE2: 0x0C, 0x01, 0x01, 0x01, 0x01 ... And so on. This seems to work fine.

RE: nRF24L01+ addressing issues

ovrebekk — Wed, 22 Feb 2017 12:03:25 GMT

Hi again

On closer inspection my test was a bit flawed. I was just measuring received packet loss, not the loss of ACK. When measuring the received ACK's (not just the received packets) I also got 100% packet loss on the worst addresses:

Lost ACK percentage: FFFFFFFFFF: 4.5% 0000000000: 100% 0100000000: 100% 0000000001: 1.4%

With the modified test I got better results when setting byte 1 to 0x4D, compared to 0x21 (< 0.5% packet loss).

RE: nRF24L01+ addressing issues

ovrebekk — Wed, 22 Feb 2017 08:54:54 GMT

Probably our address generation guide lines should be a bit more demanding. Having very few bit shifts in the address is sure to cause issues, as is addresses starting with 0x55 or 0xAA (since it matches the preamble).

I ran som tests on the addresses you mention, and my results were comparable to yours:

All 0xFF: ~5% packet loss
All 0x00: ~50% packet loss
0100000000: ~40% packet loss
0000000001: ~1.2% packet loss

If the first byte of the address is good I think you can choose the remaining bytes freely without risking massive packet loss. I did some testing on my own and found that there were plenty of options for the first byte that would yield good results even if the remaining bytes were all 0's or all 0xFF's. As an example 0x21,0x00, 0x00, 0x00, 0x00 showed 0% packet loss across the board (100 packets on 3 different frequencies, 2Mbps bitrate and the default retransmission setting of 3).

I am not able to explain why some of the poor addresses are better than others. I will check with one of the analog designers in case they have some theories.

Best regards
Torbjørn

RE: nRF24L01+ addressing issues

ovrebekk — Fri, 17 Feb 2017 09:37:05 GMT

In general you should avoid addresses with very few bit shifts, such as the ones you include here, but I wouldn't expect communication to fail completely. I will try to reproduce the issue on my end, and get back to you when I get some results.