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Shared channel dynamic device ID allocation

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Total Posts: 6

Joined 2010-10-26

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I have looked at AN07 that explains a mechanism, this explains a method to dynamically allocate slave ID's on a shared channel. As per the source code the following is stated:
aucTxBuf[0] = ASC_ACQUIRE_ADDRESS0; //write 0xFFFF as the MAC address, broadcast to all devices
aucTxBuf[1] = ASC_ACQUIRE_ADDRESS1;
If my interpretation is correct then this indicates that 0xFFFF is a send-to-all-slaves broadcast ID in the first two bytes of the data.
However the ANT usage document states:
ANT will only release the data to the slaveĆ¢??s host if the shared address field matches the shared address for that node or if the shared address holds a value 0. The master can send data to all slaves at the same time using the Shared Channel Address of 0.
and....
There is no reverse direction when broadcasting to all slaves, therefore no slaves can transmit.

Two questions arise,
1) is 0xffff as special broadcast ID similar to 0?
2) If ANT only allows a directly addressed slave to transmit data to the master then how can it respond to the aquire address process without already having an ID?

Please will somone clarify my confusion.      
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Total Posts: 662

Joined 2012-10-09

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Slaves will use the shared address 0xFFFF while they are in the handshaking stage.