Hello all,
I use DA14580 basic board and I am testing the actual interval between two notifications. Based on ble_app_peripheral project, I modify #define APP_PERIPHERAL_CTRL_TIMER_DELAY 100 only, and keep other configurations unchanged. Then I use android application to get periodical notifications. I found that the actual interval between notifications measured on the phone side is larger than what I set, my measurements:
interval_set (ms) interval_measured (ms)
20 70
30 75
50 100
100 150
400 450
1000 1050
I'd like to know why the received notification interval is larger, around 50ms more, than configured? Is there data (notification) loss? Thanks.
Keywords:
Device:
Hi Sentimental,
The fact that you send a notification at a specific time doesn't mean that the 580 will send that notification at that time. The BLE protocol doesn't have a constant communication with the other side of the link, the low energy feature is achieved because the two devices arrange their appointments for communication in constant points in time (called connection intervals), only that specific time the two devices have communication (called connection event), the rest of the time the devices are sleeping. So when you send a notification at any point of time, the device will wait until its time for a connection event, so all the notifications that you ve generated will wait until its time for the connection event and will leave the device. Regarding your experiment the approximatelly 50ms that you see is the connection interval that is used by the android devices, in most of the example applications the connection interval after a few seconds gets updated to about 20ms from the 580, so after that the notifications that you send should be more frequent. Regarding the notification loss, no there is no loss, as long as you keep sending data there is no data loss as long as you dont generate more notifications that you can send.
Thanks MT_dialog
Thanks! This detailed explanation helped a lot. I will try to change intervals on android side.