Problem reading the RPD bit correctly when Auto-Ack is turned ON.

Question

Using NRF2401+, I have two units running side by side on the bench. 
 With Auto-Ack turned OFF I can successfully read the RPD register (bit 0) and get the expected readings of 1 or 0 depending on the distance between the two modules. 
 However, when I turn Auto-Ack ON, RPD only ever reads zero even at very short range. 
 I am certain the issue is down to my code, and the point at which RPD is read. It is being read when the RX_DR interupt occurs. Any help will be most appreciated thank you!

Jon Gunnar · Accepted Answer

Hi, 
 At what data rate do you operate the chip? We have seen that the timing is very tight at lower data rates. 
 The solution you describe sounds like a good idea if you are only using it during development and not as part of your protocol. 
 Best regards, 
 Jon Gunnar

Jon Gunnar · Answer

Hi, 
 The RPD is latched at the end of a received packet and kept until you start a new receive window. In Auto ack mode, a new receive window will begin after sending an ACK as response to a received packet. This means that you'll have a short window from RX_DR gets set until RPD is cleared. 
 Please review the timing for when you actually read RPD to see if this can be the case. 
 
 Best regards, 
 Jon Gunnar

Problem reading the RPD bit correctly when Auto-Ack is turned ON.

Top Replies