Hi WenZhan, The only access you have to the Bluetooth inside the WL183x device is via an HCI interface over UART. There is no specification I am aware of that would allow you to infer time of Rx/Tx at the bluetooth physical layer from the time the HCI interface delivers information.
If you are looking to do time sychronisation within a network then the wifi part of WL183x has the option to do that http://processors.wiki.ti.com/index.php?title=WL18xx_Clock_Synchronisation_with_NTP_in_SDK3 This uses the Access Points Wi-Fi beacon to synchronise all the stations connected to the AP. It was done on BBGW using TI's SDK. You would need to merge some of the specific time synchronisation code from TI's R8.7 driver release into a mainline kernel to get it working on a current kernel. Iain On Wednesday, September 12, 2018 at 3:27:45 AM UTC+1, WenZhan Song wrote: > > Thanks for reply! But Bluetooth speed itself is not a decision factor of > time sync accuracy as time sync message is small, we only concern about the > delay/jitter caused by Linux OS - or perhaps it is not a concern at all? We > will find out. Thanks! > > On Tue, Sep 11, 2018 at 5:52 PM, Robert Nelson <robert...@gmail.com > <javascript:>> wrote: > >> On Tue, Sep 11, 2018 at 4:29 PM WenZhan Song <wenzha...@gmail.com >> <javascript:>> wrote: >> > >> > Robert, >> > >> > Thank you for replying our questions! To be clear, what we intend to do >> is: we want to design a time synchronization protocols among a group of >> BBBWs using the bluetooth radio in BBBW, with the goal to achieve 10 us >> accuracy. Thus, we want to program PRU to send and receive bluetooth >> messages with low-level timestamping for that accuracy. The hypothesis is >> that ARM with Linux perhaps has too much uncertainty and delay while PRU >> can reduce that. >> >> and "how" exactly is the PRU going to reduce that? It doesn't control >> the radio directly... >> >> > Is this possible? If not, do you happen to know any mature way to >> achieve 10 us accuracy with Bluetooth or WiFi radio. I currently use GPS >> but it does not work well indoor. >> >> PS, If you look at: >> >> http://blog.bluetooth.com/exploring-bluetooth-5-how-fast-can-it-be >> >> It would be better to just use a Bluetooth 5 usb dongle.. >> >> Regards, >> >> -- >> Robert Nelson >> https://rcn-ee.com/ >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/f48353e0-29b3-43b1-94e4-973043e70d17%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
