Hi Christian, The connection interval determines how often the two devices can talk over the radio, and the connection event length determines the number of transactions that can happen each connection interval. With a minimum of 20ms, you are correct that on average, you will be in the middle of the interval, so the time to send a command will be 10ms. If the command does not require a response, then you can send multiple commands in one connection interval. If the command does require a response, it will take two connection intervals per command (one for the request, and one per response). There are other factors that can affect things (queuing time in the radio, interference, other queued packets), but that’s a good place to start. - Craig
On Jan 29, 2016, at 5:10 AM, Christian Ridderström <christian.ridderstrom@gmail.com> wrote:
Hi,
I'm interesting in sending a command from an iOS device over BLE to a piece of hardware and wonder what kind of delay i could expect when trying to make it as fast as possible?
From reading documents etc, I've understood that the lowest connection intervall for iOS is 20 ms [*]. And also that writing a characteristic without an acknowledgement is faster. So let's assume the iOS device is the central device, and that the app at some point in time initiates writing a characteristic without acknowledgement. Should we then expect the peripheral device to have received the value at say 1 ms to 20 ms later (uniformly distributed)?
Is this correct, or could the delay be even larger?
Can we make the delay smaller somehow? E.g., I think I've read that iOS can send up to four ... "packets" in one intervall, does this mean it's somehow possible to reduce the maximum delay to 5 ms, e.g. by writing the same command four times?
Best regards, Christian Ridderström
[*] Unless it's a HID, in which case it's 11.5 ms.
-- Christian Ridderström, +46-70 687 39 44 _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/cdooley%40apple.com
This email sent to cdooley@apple.com
_______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists.... This email sent to site_archiver@lists.apple.com