Error Writing Large Characteristics

RE: Error Writing Large Characteristics

Petter Myhre — Tue, 25 Oct 2016 14:51:09 GMT

Great that you got it working.

Thank you for the feedback, I'll relay that to the developers, but which example are you referring to?
You should be able to calculate the size by using this.
This is an alternative. With this approach I guess you can copy the data in as it comes, but then if you get link loss only a part of the data may be valid.

RE: Error Writing Large Characteristics

Bill Finger — Tue, 25 Oct 2016 12:32:27 GMT

Peter,

Thanks, your reply led me to the answer. In response to BLE_EVT_USER_MEM_REQUEST I was calling sd_ble_user_mem_reply() with a NULL mem_block, just like in the template example. If I instead provide a large memory block, the long write works.

If I may, a few comments.

It would be nice if the template example illustrated this technique, even if it isn't technically necessary.
It would be nice if the documentation for either BLE_EVT_USER_MEM_REQUEST or sd_ble_user_mem_reply() indicated what size the memory block should be, and under what conditions it was needed. Right now the documentation for sd_ble_user_mem_reply() is "Provide a user memory block."
Why is this even necessary? I am using a user-buffer for the characteristic. Why can't I just copy the data into it as it comes? RAM is very tight in my application.

Regards, Bill

RE: Error Writing Large Characteristics

Petter Myhre — Tue, 25 Oct 2016 11:24:26 GMT

I'm not an Android expert, but Aleksander Nowakowski is, and according to him it should work. How are you handling this in the peripheral application? If you have Sniffer traces, could you edit your question and upload them?