Notify arrives late (timing problem)

[Chris G.]

Hey guys. We are using the NRF52 with SDK 13.0.0.1-alpha. If we connect the NRF52 to our own android or iOS APP we have some timing problems with notifications. When the smartphone is connected to the NRF, the user writes from smartphone into a characteristic(rx) and gets an ACK in another characteristic(tx) over notify. The problem is that the notification arrives only after 300ms and we dont know why.

Following things we already have tested: (1) If we send for example 100 notifications in a row we get them very fast(about 30 notifications a second) (2) Disable other bluetooth devices, so that we dont have traffic from other advertisements. (3) We traced the time(start: on_write(rx) event until send notification on tx) and we only need 0,20 ms. I hope you can give me some information :)

[FormerMember]

Do you see the same problem if you use nRF Connect (iOS)?

How do you enable the notifications?

[FormerMember]

Setting char_md.char_props.notify = 1 will only set the notify property. However, the notification will not be enabled that way. To enable notifications for a characteristic, the client (often central/master) has to enable notifications by writing to the CCCD of the given characteristic.

In nRF Connect, there should be a button for enabling notifications for each characteristics that have the notify property.