Ant ACK retries

Question

Hi Nordic, 
 I am now trying to use ANT acknowledged data type in reverse direction (from slave to master), and I have some questions: 
 
 
 When sometimes, ack signal fails, internally, how many retries are configured? Can this number of retries be changed in the ANT stack, or I have to do it by software? 
 
 
 The ACK message, does it bring information about the whole message it is replying to? I mean, is there any difference between an ACK message received for message 1 and for message 2? 
 
 
 What is usually the time that it takes to receive the event TRANSFER_TX_FAILED? Can this time be configured? Does it depend on the channel period? 
 
 
 Thanks! 
 PS: S210 v5.0.0, nRF51422.

Petter Myhre · Accepted Answer

This seems to be described in Section 9.5.5.2 in ANT Message Protocol and Usage 5.1, on Page 103: 
 
 
 Acknowledged data messages can be sent
from a slave to a master. In this case
the message is sent immediately after
a message is received from the master.
If the acknowledged data message is
sent successfully, this will be
indicated by the channel event
TRANSFER_TX_COMPLETED. If no
acknowledgement is received from the
master, this will be indicated by
TX_TRANSFER_FAILED, which either means
that the message failed to reach the
master, or that the response from the
master failed to reach the slave. In
this case the slave’s application
layer may retry the message. A third
possible scenario is that the channel
is dropped and the slave begins to
search; in this case the event
GO_TO_SEARCH will be received, instead
of either of the other two commands.
If GO_TO_SEARCH is received then the
acknowledged message will not be sent,
and the channel should be unassigned 
 
 
 I dont' understand. What kind of information? 
 Depends on when you tell the stack to send the message, and the channel period. See the Figure 9-2 for more information.

Ant ACK retries

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