ANT Time Synchronization Example Understanding

RE: ANT Time Synchronization Example Understanding

Petter Myhre — Tue, 20 Sep 2016 10:56:16 GMT

They are going to release an app note explaining this.

RE: ANT Time Synchronization Example Understanding

Petter Myhre — Mon, 19 Sep 2016 10:40:09 GMT

Yes, I know. But that is what the flag byte is. To me it almost seems that Dynastream is going to release a new spec or something. I will try to contact them.

RE: ANT Time Synchronization Example Understanding

Tron — Sat, 17 Sep 2016 12:14:55 GMT

Now i had time to think about your answer and I think there is a problem. If the flag byte is 0x20 then there are only two bytes for "RX timestamp" information, see page 36 of ANT_Message_Protocol_and_Usage_Rev_5.1. But in the receive example they access four bytes ( pstEventMessage->ANT_MESSAGE_aucExtData[0] to pstEventMessage->ANT_MESSAGE_aucExtData[3]).

RE: ANT Time Synchronization Example Understanding

Petter Myhre — Fri, 16 Sep 2016 16:22:03 GMT

It depends a bit, they obviously know most about how their stack works, but we will try to help you as best as we can.

RE: ANT Time Synchronization Example Understanding

Tron — Fri, 16 Sep 2016 14:43:52 GMT

Thanks for the answer! Yes, I posted the question also on their forum. Just for upcoming questions, which forum should I use for ANT Softdevice questions?

RE: ANT Time Synchronization Example Understanding

Petter Myhre — Fri, 16 Sep 2016 11:12:46 GMT

I think I know what it does, but I think you have to wait for Dynastream to confirm it. It saw that you posted a question on their forum.

This is what makes sense to me:

sd_ant_time_sync_broadcast_tx() is called with the count of RTC1. When the ANT stack actually sends the packet it will exchange this count with the current count of RTC1 - count = offset.
When the packet is received, the ANT stack will time stamp the count of RTC1, and send it up to the application.
The CC value of RTC1 is set to time stamp - offset + LED_INVERT_PERIOD.

The flag byte is 0x20, RX time stamp.

It seems to me that are some (serious) lack in the documentation, but we will see what they say on the Dynastream forum.

Edit: What they said on the Dynastream forum.