Re: [Bluez-devel] absolute clock

Steven Singer
2004-03-31T11:58:47Z

paolo2278@freemail.it wrote:
> I have a great problem, I'd like to know wich is the structure where I
> can find the value of the bluetooth's absolute clock, or the function
> that I could call for read this value.
[...]
> P.S. I have a CSR Bluetooth

As Marcel pointed out in another message, there's no standard HCI
command to read the Bluetooth clock in BT 1.1 but there is in BT 1.2.

However, if you have a CSR BT 1.1 device there are vendor specific
commands. If you use CSR's BCCMD mechanism then there are two IDs of
interest: BCCMDVARID_BT_CLOCK (0x2c00) returns the local Bluetooth clock
of the controller; BCCMDVARID_PICONET_INSTANT (0x3009) returns the
current Bluetooth clock for the a given piconet (it expects you to pass
in an ACL handle for any link on that piconet).

If you have access to the CSR support website (www.csrsupport.com) then
it's all fully documented. Don't forget that you may need to tunnel the
commands over HCI. Alternatively, you might find it easier to dig through
the BlueZ source and find out where it sends the commands to change the
uart baud rate - that should give you a good example to work from.

I can't recall if BlueZ has a tool that allows you to send arbitrary
BCCMDs to CSR chips - if not, it sounds like a good project for
someone.

- Steven
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