experimental_ble_app_uart on nRF51-dk

[Milan]

Hello there,

I am using the experimental_ble_app_uart with S110 on nRF51-dk and receiving sensor data via 1MHz SPI every time the timer ticks = 100ms. Data transfer displayed on nRF Toolbox works fine but when I disconnect the application and trying to connect back again to the dev kit I receive an error shown on image below. It can be seen that the system returns an error after 20 second which I could not reference to and I suppose it is either a soft device timer or application.

Could you please explain what is going on and why the connection cannot be instantiated again after disconnection? After the error message appears I am able to connect to the dev kit again on the first time however it just seems like that after disconnecting the dev kit doesn't advertise again only until the error where the state is updated and advertising allowed again.

I also include the time stamp image of data transfer where I am wondering that what is causing the discrepancy of 100ms timer? (APP_TIMER_TICKS(100, APP_TIMER_PRESCALER) In some cases it is too far from 100ms.

Many thanks

Milan

[Asbjørn]

The disconnect and time it take for it to start advertising again is most likely related to the time out of the supervision timeout for the connection on the nRF51. Until you reach this point, the nRF51 will consider the link still valid and just try to re-transmit.

Regarding the drift in app_timer. What clock source do you use? Are you running any BLE traffic at the same time?

[Milan]

Interesting because when I disconnect the app from the service it reads service destroyed.

The app is based on experimental_ble_app_uart wich is using 32kHz clock and no scheduler.