RE: Does nRF24L01+ sends negative ACK packet if checksum has failed at receiver?

Asbjørn — Fri, 28 Nov 2014 07:42:51 GMT

In the case where the Primary transmitter (PTX) send a package, but the Primary receiver (PRX) receives it with an invalid CRC, the PRX will discard the package and not send any ACK at all. You won't know whether or not the error was in the payload or in the addressing itself. The principal is that the ARD will time out on the PTX side and the PTX re-transmits the lost package.

The ACK from the PRX to the PTX is by default an empty package and the reason for why the PTX checks for payload in the ACK is that this feature is optional and there could potentially be a user defined payload in the ACK. There's no good or bad indication in the payload informing you on the status of the initially received package outside the fact that if it was good and the CRC was correct, the PRX sends an ACK. If something was wrong with the CRC, the PRX will never send the ACK.

RE: Does nRF24L01+ sends negative ACK packet if checksum has failed at receiver?

Paul — Fri, 28 Nov 2014 01:08:14 GMT

My memory tells me there is no indication/RF back saying CRC is wrong.