Do we know the time needed to write a characteristic from central?

[Ron]

I'm using 2 nrf51 DKs one as central and one as peripheral. I'm wondering if there is a defined time that a write takes to be registered on the peripheral?

[Stefan Birnir Sverrisson]

Hi Ron

I am not sure about what time you mean. Are you talking about the time from when a central device application issues a write, until the write value is stored in the peripheral database? If so, I suppose it mostly depends on the connection interval of the connection. The minimum connection interval is 7.5ms, which would be the time the packet needs to wait on the central side, worst case, until it can be transferred over the air. I suspect the processing delay of the softdevice on the central side and the processing delay on the peripheral side are together less than 1ms, so it would mainly depend on the connection interval. But as with any other wireless communication, packets can be lost, which would require a retransmission, which would mean additional delay.