ANT Forum

I am going to be implementing bidirectional mode for the first time (shared channel). After the slave receives a message from the master how long does it have to send its reponse before the master decides that no response is coming?

I am using the Nordic nRF51422 and am assuming after I receive the message I have some time to parse it, build the response packet and then send it, but have no idea what this time range is. Thank you.      

Hi ScottB,

I would assume that you won't have time parse, build and send the response if the shared slave is only addressed once. I would recommend that the master polls the slave twice, such that response the slave sends in response to the first message actually gets sent in response to the second message received from the master.

Once you 'send' the data from the application layer, it will sit in the transmit buffer and immediately be sent the next time the slave is addressed by the master.

Of course if you already know what the master will request, you can send the message ahead of time to have it transmitted on the first message.

Hope that helps,

Kat      

Kat,

Thanks for the reply. I am assuming from what you said is that when a device is a slave, when you submit a packet for transmission, it will sit in the buffer until the slave receives a message from the master and then the ANT layer will automatically send the waiting message out, so I can submit a reply message at any time and expect it to go out the next time a message is received. Is that correct?      

Yes that's correct. Additionally in the case of a shared channel, the message won't go out until the master addresses that slave (this avoids issues with all slaves replying at once and the messages colliding).