Enhanced Shockburst mode with out pre-loaded reply

[Gustav]

I am using the nRF24le1 in Enhanced Shockburst mode.

The datasheet describes how it is possible to upload acknowledge packets, W_ACK_PAYLOAD, to the TX FIFO. And then the PRX will send the acknowledge as soon as it receives a packet.

I would like the PRX to give immediate response to back to the PTX, based on the content of the packet is has just received.

Is it possible for the PRX to upload W_ACK_PAYLOAD as soon as it receives a packet and send acknowledgement back with reply to the packet from the PTX? From my own testing, it seems like there is a time-window of about 120us, between receiving a packet and before the a W_ACK_PAYLOAD has to uploaded.

Alternatively, I will have to send two packets from the PTX: 1) The first with data to PRX. 2) The next, (a dummy), to get an acknowledgement with feedback on the data in the first packet.

In other words: Is Enhanced Shockburst mode possible without pre-loaded acknowledgement packets? And if so, how big is the time-window?

[ovrebekk]

Hi

I would recommend going for the two packet solution, where you send a second dummy packet to pick up the ACK payload.

It is possible that there is a time window in which you can actually upload a packet and have it sent immediately, but this hasn't been tested by us so please use it at your own risk ;)

Regards Torbjørn

[Gustav]

Hejsan Torbjørn,

Thanks for your answer, but it came too late. In the last couple of days, I have worked hard to verify the solution with immediate acknowledge. It seems to work. There is even a reasonable safety margin.

I will take your reply into account, and be extra careful not to have any unnecessary delay between packet received and upload of acknowledge. This solution makes my software so much simpler.