Device Address match

[Sean]

I have two questions.

1. Is it possible to use the DAP[n]/DAB[n] registers without using Bluetooth 4.0?

2. If it is possible, then how? I searched all the sample code, and couldn't find anything. Furthermore, I read the reference manual for the nRF51822 and there was only one paragraph (16.1.13) on the topic.

I just want to use a host to listen for 5 devices using the radio. No s110 or s120 bluetooth stack. I don't want to use Gazell or Ant. I want my own stack. The reason is that since s110, s120, Ant and Gazell do not allow me to see the source code (since it is already precompiled) I can't learn anything. I don't believe in blindly trusting someone's code. I'm sure their code is good, but I would like to tailor the code to my application, and thus optimize it.

[Ole Morten]

As is explained in section 16.1.13, these registers are made for doing address whitelisting, as is used in the Bluetooth specification. Unless your on-air frames use the same format as BLE, they won't really be very useful for your own protocol.

The reason they're useful in BLE is that all packets going on the advertising channels use the same access address (HW address as seen by nRF51), but the device that sends the packet's address is part of what is considered a payload by the nRF51 radio. Hence, normally the firmware would have to read out the packet payload, and then do a manual compare with the address of the device it wants to receive for instance a connection request from. However, using this feature instead, the HW will do the matching for it, and it can just use the result.

As section 16.1.13 says, you should refer to the Bluetooth specification to understand how this works. See for instance Volume 6, Part B, section 2.1 and 2.3.