Hi,
I'm using the S110 v7.10 to implement a service with an RACP, amongst other things. I'm supporting multiple transmissions per connection interval. This is working fairly well at the moment but has a minor timing issue. Before I try to fix it, I'd like a better understanding of the buffering for notifications and indications.
I've already read the following (as well as other related posts): devzone.nordicsemi.com/.../ devzone.nordicsemi.com/.../
So I realize that notifications use the "user" buffers while indications use the "system" buffers. I'm also aware that notifications are sent in a FIFO manner once queued. I assume the same applies to indications. But i'm unclear on what other guarantees, if any, are made about transmissions from these buffers. For instance:
- If I successfully queue a notification or indication using sd_ble_gatts_hvx, is it guaranteed to be sent on the next connection interval? If not, in what situations would it not be sent in this interval?
- If there are packets queued both in the user buffer and the system buffer, which get sent first?
- A specific example of the above: if I successfully queue a notification followed immediately by an indication, can I rely on a consistent transmit ordering (and what is that order)?
- Presumably the buffers are cleared if the connection is lost. If I send a notification and then the connection is lost before the notification is sent, do I get a TX_COMPLETE event (this is important if keeping track of free buffers).
As an observation, the buffering appears to be a commonly misunderstood feature (given the number of posts relating to it). It'd be good to get a detailed description of this in the API documentation.
Thanks, Carl
