rtt when link disconnected

RE: rtt when link disconnected

Bjørn Kvaale — Thu, 21 Sep 2017 07:05:00 GMT

This case might be able to help you out.

RE: rtt when link disconnected

paul_tanner — Mon, 18 Sep 2017 13:28:17 GMT

Thx.

OK. so there's some other issue. I removed all the RTT calls and the problem is the same. The timeout seen by the phone app is caused by the example crashing before BLE is connected.

So evidently I have a hardware problem. I have tried additional pullup and down on the SWDIO and SWDCLK. Does not fix it. Neither does pulsing nRESET pin low.

Could the JLink have put the nRF52 in some mode where it needs to remain connected? Just guessing.

RE: rtt when link disconnected

RK — Mon, 11 Sep 2017 20:17:53 GMT

No. RTT uses a fixed sized ring buffer which is overwritten if it fills up. RTT was designed to be able to be left in your code as it just harmlessly writes data, if a Segger isn't connected, it just doesn't get read or go anywhere.

Segger used to have a much better description of RTT than it seems to now, there's an old copy of it www.phaedsys.com/.../seggerjlinksw.html which has the original description of the ring buffer and a comment you can use it without a debugger connected.

So that's most likely not your problem.