RE: Link loss troubleshoot

FormerMember — Mon, 06 Oct 2014 12:46:20 GMT

First, I would recommend you to use the sniffer to track what is being transmitted over the air.

Secondly, do you have hardware flow control enabled (HWFC)? If not, you should do so: To use UART with softdevice , you need to have HWFC enabled. Otherwise you may experience that data is overwritten in the nRF51822 UART RX buffer. That is because the softdevice blocks the CPU for 1ms-6ms, depending on the amount of data you are transmitting in each connection interval.

The problem may also be related to iOS, make sure that you follow Apple's guidelines on connection parameter settings, see this document, section 3.6.

Update: Another possible reason for the problem is that the UART works fine. However, the BAUD rate for the UART is higher than what the nRF51822 is able to transmit over the air. This will lead to a TX buffer that is "overloaded" on the nRF51822, and result in a disconnect. The disconnect can be avoided if the nRF51822 stop receiving data over UART when the buffer is full. One of the UART examples on github should implement this "feature".