getting NRF_LIBUARTE_ASYNC_EVT_OVERRUN_ERROR after long time of use

[Roy@techpacklab]

Hello,

im using nrf52840 with sd140 and sdk17.0.1

in my project i have implemented a libuarte communication that works well usually, but rarely, and usually after days of running i get this error:

NRF_LIBUARTE_ASYNC_EVT_OVERRUN_ERROR

i do nothing to handle this error and continue regularly and after this i start getting jumbled strings from the libuarte.

meaning if i send something like this:

"

123456789

123456789

123456789

123456789

abcdefghijklmnopqrstvuwxyz

"

i might get something like this:

"

123456789\n

123456789\n

123456789\n

123456789\n

abcdefghijklm123456789\n

nopqrstvuwxyz

"

i have seen a similar question in the following link:

https://devzone.nordicsemi.com/f/nordic-q-a/63905/libuarte-issue-nrf_balloc_alloc-retuns-null-after-a-while

and it ended up in saying that it got resolved somehow with the timers, which i kind of suspected,  but still don't know how to resolve.

i init the libuarte by:

NRF_LIBUARTE_ASYNC_DEFINE(xxxxx_libuarte0, 0, 1, 2, NRF_LIBUARTE_PERIPHERAL_NOT_USED, ATCMD_LIBUARTE0_RX_BUF_SIZE, ATCMD_LIBUARTE0_RX_BUF_CNT);    // using uart0 ; TIMER1; RTC2

this problem is very rare which makes it difficult to debug. 

please advise,

Regards,

Roy Barak

TechPack Lab

[Roy@techpacklab]

Hi Simon,

i have some update, in the latest version i have enabled the HWFC and the bug also returned, although it took much more time and attempts to reproduce the bug (over a week when before it took 2-4 days top).

i do not know if this has something to do with the HWFC enabling or just a fluke (as this is a rare bug to begin with), we are running this again to get a better statistic.

do you have any thought if the enabling of the HWFC might only solve this sometimes?

if so, do you have a solution to the remainder?

any other ideas?

if this will not be solved, then we will need to find acceptable bypass solutions, the simplest one is reset, but for the system it might complicate things, can you suggest a cleaner solution? possibly resetting only the libuarte and re-init it will work?

Regards,

Roy.

[Simonr]

Hi

I'm guessing the HWFC might be "stalling" the error for some time, but that it does not solve the problem. The only other suggestions I have is that this is likely caused either by the buffer_size or the timeout of your libuarte implementation. Can you try tweaking these somewhat to see if that helps?

As a back-up plan, I guess you can try just disabling and enabling the libuarte peripheral, but you should test this to make sure it works.

Best regards,

Simon

[Roy@techpacklab]

Hi,

yes, i figured that this is the next step and modified the libuarte init.

from:

#define ATCMD_LIBUARTE0_RX_BUF_CNT 3

#define ATCMD_LIBUARTE0_RX_BUF_SIZE 255

NRF_LIBUARTE_ASYNC_DEFINE(atcmd_libuarte0, 0, 2, NRF_LIBUARTE_PERIPHERAL_NOT_USED , 3 , ATCMD_LIBUARTE0_RX_BUF_SIZE, ATCMD_LIBUARTE0_RX_BUF_CNT); // using uart0 ; TIMER2; TIMER3

to:

#define ATCMD_LIBUARTE0_RX_BUF_CNT 9

though i believe that this is more avoiding the issue then handle it, since i just increased the buffer so it will probably never (or much more rarely) will get overflowed.

it is running for several days now, will update regarding results.

Regards,

Roy