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Spirit1 STack packet ACK - what is it?

Scott Löhr
Senior II
Posted on July 14, 2016 at 20:18

While I await some expert help on the question about a packet sniffer for the STack protocol, can anyone describe what is the ACK in the STack protocol? What does it look like (i.e. does it have a preamble and/or sync and/or CRC)? What is it's payload, just some random byte or bytes? Any specific values?

Thanks...

1 REPLY 1
Scott Löhr
Senior II
Posted on July 15, 2016 at 19:20

Dear ST - I am desperately awaiting any hints on my questions wrt Spirit1, any insights will help this proof-of-concept fly, otherwise I may lose the interest of my managment.

Another detailed question wrt the STack packet protocol auto-ACK:

I seem to have empirical evidence that the Rx side will auto-ACK even when there is a CRC error. As you know from my other question, I have to STack packet protocol sniffer, but running both Tx and Rx sides from the debugger shows that the Tx side gets no interrupts with 'IRQ_MAX_RE_TX_REACH' set during a burst of messages while it does get the expected number of interrupts with 'IRQ_TX_DATA_SENT' set. And for the same burst of packets, the Rx side usually gets multiples of 3 interrupts with 'IRQ_RX_DATA_DISC' / 'IRQ_CRC_ERROR' and then the count of 'IRQ_RX_DATA_READY' interrupts, the sum of which equals what the Tx side sent.

Is this possible that the auto-ACK feature does an ACK even when the data is discarded?