NRF log RTT small buffer size when device is disconnected

[vitaliy2034]

When I reset the device and in some time connect it to JLinkRTTViewer, it shows only 11-12 first messages after the reset. Which parameter I should change to increase number of messages? I use in-place processing, RTT backend and NRF_LOG_ALLOW_OVERFLOW are turned on.

[Vidar Berg]

Hello,

With NRF_LOG_ALLOW_OVERFLOW  enabled I would have expected the it to continue logging even if the message buffer was too small because this setting allows the logger to overwrite old messages.

Apart from the missing logs, does your device appear to function normally, or is it possible that it may have "crashed"?

[vitaliy2034]

Sorry, for late answer. No, device works properly.

[Vidar Berg]

Have you tried to replicate this with some of the other original nRF5 SDK examples to see if maybe the issue only affects your code? And have you tried to update the Jlink drivers?

[vitaliy2034]

Hello, I have found parameter in sdk_config.h which response for buffer size: SEGGER_RTT_CONFIG_BUFFER_SIZE_UP .

But RTT behavior if the buffer is full supports next modes(Parameter SEGGER_RTT_CONFIG_DEFAULT_MODE):

SKIP  - Do not block, output nothing.
TRIM  - Do not block, output as much as fits.
BLOCK - Wait until there is space in the buffer.

How to use NRF_LOG_ALLOW_OVERFLOW, I don`t know.

[Vidar Berg]

What do you have 'SEGGER_RTT_CONFIG_DEFAULT_MODE' set to? Our SDK examples use SKIP.