flashlog loses pushed string contents

RE: flashlog loses pushed string contents

Hung Bui — Fri, 14 Jan 2022 09:10:00 GMT

Hi Brian,
Thanks for the info. I think we have an idea of what could be wrong here.
Since you declared the p_dt as static string, the logger module would assume it's a static text, just like the other text "Entering state idle2" and use a reference to it like what Vidar explained. But the problem is that it's stored in RAM not flash. So when you have a power reset, the static string is gone and you don't see it anymore.
But when you store them as integer ( I would assume without static ) it's treated as variable and will be stored as a new entry in flash log every time you push.

RE: flashlog loses pushed string contents

Brian — Fri, 14 Jan 2022 00:17:19 GMT

I was able to resolve this by storing my RTC data as multiple separate integer values rather than just one string. I believe this allows each value to be stored in the flashlog rather than a pointer to a single location.

RE: flashlog loses pushed string contents

Hung Bui — Thu, 13 Jan 2022 16:53:30 GMT

Hei Brian,

I'm sorry for late response. Jared is on vacation so I will take over the case.

If you have a look at this case handled by Vidar : https://devzone.nordicsemi.com/f/nordic-q-a/58111/implement-flashlog-backend

He explained a little bit more about how flashlog is stored and on that the variable is stored at a different location compare to the static log (e.g "Entering state idle2") . It may explain why you only see the static one not the date and time.

RE: flashlog loses pushed string contents

Brian — Thu, 30 Dec 2021 15:46:21 GMT

Hi Jared,

I'm using SDK 17.0.2.

After a power cycle, p_dt contains the address of the variable dt_str (0x2000 d548). dt_str is the statically-declared variable that gets updated by the logging_datetime_get() function -

#define DATE_TIME_STR_SIZE 32

static char          dt_str[DATE_TIME_STR_SIZE];
static char*         month_str[NUM_MONTHS + 1]  = {"Inv", "Jan", "Feb", "Mar", "Apr", "May", "Jun",
                                          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

char* logging_datetime_get(void)
{
    error_status_t err;
    date_time_t    date_time;

    err = pcf8563_datetime_get(rtc_handle, &date_time);

    if (err == ERROR_OK)
    {
        (void)snprintf(dt_str, DATE_TIME_STR_SIZE, "(20%02d-%s-%02d: %02d:%02d:%02d)", date_time.year,
                       month_str[date_time.month], date_time.day, date_time.hour, date_time.minute, date_time.second);
    }

    return dt_str;
}

I understand that after a power cycle, p_dt will not point to the correct timestamp data for previous entries in the flashlog. My assumption was that using NRF_LOG_PUSH would save the contents of the string, which in this case would be the timestamp when the event was first logged.

Thanks.

Brian

RE: flashlog loses pushed string contents

Jared — Thu, 23 Dec 2021 12:19:16 GMT

Hi,

What SDK version are you using?

After the power cycle, could you pause the application after logging_datetime_get() with a debugger and see what p_dt is set to in debug view?

regards

Jared

Also, we're short on staff due to the Holiday season. Expect some delay in the handling of this case.