Revision 1.0

Page 18 of 44

nRF24AP2-USB Product Specification

4.2.5

Continuous scanning mode

Continuous scanning mode allows for fully asynchronous communication between an ANT node using

continuous scanning mode, and any other ANT node using a standard master channel. This has two main

advantages over only using standard ANT channels. The first is that the latency to initiate communication

with the scanning node is reduced to zero and every message sent by a master channel in proximity will be

received by the scanning device. Secondly, the requirement to maintain communication for the purpose of

synchronization while in proximity is removed. This means that it is possible for nodes to come and go very

quickly or to turn off for long periods of time in between communication events. This saves power on the

transmitting node.

The disadvantage of continuous scanning mode is that it consumes much more power than standard ANT

channels. Therefore, continuous scanning mode will typically be used only on devices that are plugged in

and not mobile such as a computer (USB dongle). Another disadvantage is that a node in scanning mode

can no longer be configured to have discoverable master channels because scanning mode disables stan-

dard ANT channel functionality. It is worth noting that two ANT nodes in scanning mode cannot communi-

cate with one another because neither will be able to spontaneously generate communication.

Standard ANT channels are recommended over scanning channels, even in dynamic systems where

devices are coming and going. This is because scanning channels are not recommended for a mobile

network, which is the primary use case for ANT. Scanning channels will typically be used in statically

located networks where the scanning channel node is plugged in and not mobile.

4.2.6

ANT network topologies

By combining ANT channels with different features depending on local needs, you can build anything from

very simple peer-to-peer links and star networks to complex networks as shown in Figure 10. on page 19.