How to get ANT tx timestamp

RE: How to get ANT tx timestamp

bgarrood — Thu, 27 Jan 2022 08:45:04 GMT

Understood. Thanks again for the help. With this in mind I think I can figure out what I need with logic analyser.

RE: How to get ANT tx timestamp

Kenneth — Thu, 27 Jan 2022 08:38:58 GMT

I would expect these events to be pretty consistent for a specific configuration at least, but if you do changes (e.g. add more channels etc) then I suggest to re-verify the timing.

Kenneth

RE: How to get ANT tx timestamp

bgarrood — Wed, 26 Jan 2022 13:44:40 GMT

Oh yes, good idea. Thank you. Do you expect the time offset between actual ANT RX and RX event firing (I measure approx 0.2ms by comparing ANT timestamp to RTC clock value in ant event handler), and actual ANT TX and TX event firing to be consistent?

RE: How to get ANT tx timestamp

Kenneth — Wed, 26 Jan 2022 13:27:32 GMT

I was thinking to simply toggle a GPIO when the mentioned events occur, and measure the distance on a oscilloscope or logic analyzer. What is your timing accuracy requirements here? If it's in the few tens of uA this should be fairly straight forward as mentioned, if you require few us, then I don't expect you will be able to do this in any way.

Kenneth

RE: How to get ANT tx timestamp

bgarrood — Wed, 26 Jan 2022 13:10:46 GMT

Thank you Kenneth. Do you have any links showing how to use a logic analyzer, in particular to compare timings of slave and master events? I am using segger embeddded studio.

RE: How to get ANT tx timestamp

Kenneth — Wed, 26 Jan 2022 12:27:31 GMT

I don't know how accurate you need the timing here, but typically it should be a pretty consistent and fixed offset between the data sent event on the master and data received event on the slave, so if you measure with a logic analyzer the timing difference between the two events, you should be able to use this offset to compensate relatively accurate in general. I am not aware of any other way of doing this really.

Kenneth