TudorS.

Kinetis W-Series Active Promiscuous Mode

Discussion created by TudorS. Employee on Oct 6, 2014

Kinetis W-Series Active Promiscuous Mode

 

This is an IEEE 802.15.4 Rx mode for the Kinetis KW wireless platforms that works somewhat like a typical promiscuous mode meaning it forwards any packet that passes CRC check to an upper layer, without applying any address or security filtering rules. The main difference from the typical scenario is that the wireless platform is sending ACK packets that are addressed to it.

The active promiscuous device can become a very powerful commissioning tool for networks, by being able to monitor and configure the PAN at the same time. Basically it can be a smart sniffer that acts also as a node in the respective network.

Special rules apply to received packets that contain a broadcast PAN identifier (0xffff) and/or a broadcast short address (0xffff) according to the 802.15.4 standard. For valid frames that are not broadcast, if the Frame Type subfield indicates a data or MAC command frame and the Acknowledgement Request subfield of the Frame Control Field is set to one, the MAC sublayer shall send an acknowledgement frame. An exception is made for received packets that contain a broadcast PAN identifier and a long address that matches the device's IEEE address. Such packets are acknowledged because the IEEE address uniquely identifies the device regardless of the PAN. This special case will also apply in "Active Promiscuous" mode where such packets will be acknowledged. The following table describes the "acknowledgement decision" for all permutations of broadcast indicators in the received packets addressing fields:

 

act.png

 

The programming interface for this mode is very simple. For instance, the KW2x wireless SiP, only has a -1-bit register ACTIVE_PROMISCUOUS that can turn on or off this feature. 

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