Lpc2000

The RTC day-of-week (DOW) register does not appear to automatically
reflect the correct day of the week based on a correctly set month,
day-of-month, year in the RTC.  Is this calculation supposed to be
done automatically in the RTC or is it just a modulo 7 counter (i.e.
do I need to set it to the correct day of week when I set the RTC date?)

Yes - you need to set it in software.  The hardware does not do that
calculation.

--
Jim Parziale
nuncio.bitis@...
Malden, MA

On 4/3/06, dave_albert <david_albert@...> wrote:
>
>  The RTC day-of-week (DOW) register does not appear to automatically
> reflect the correct day of the week based on a correctly set month,
> day-of-month, year in the RTC.  Is this calculation supposed to be
> done automatically in the RTC or is it just a modulo 7 counter (i.e.
> do I need to set it to the correct day of week when I set the RTC date?)
>
>


[Non-text portions of this message have been removed]

Yes, the DOW counter it's only a modulo 7 counter, so
you need to calculate this value prior writing to this
register (same DOM and DOY).

Regards,
Boby

--- dave_albert <david_albert@...> wrote:

> The RTC day-of-week (DOW) register does not appear
> to automatically
> reflect the correct day of the week based on a
> correctly set month,
> day-of-month, year in the RTC.  Is this calculation
> supposed to be
> done automatically in the RTC or is it just a modulo
> 7 counter (i.e.
> do I need to set it to the correct day of week when
> I set the RTC date?)
> 
> 
> 
> 
> 


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dave_albert wrote:

>The RTC day-of-week (DOW) register does not appear to automatically
>reflect the correct day of the week based on a correctly set month,
>day-of-month, year in the RTC.  Is this calculation supposed to be
>done automatically in the RTC or is it just a modulo 7 counter (i.e.
>do I need to set it to the correct day of week when I set the RTC date?)
>
>
>  
>
Correct, you are responsible for setting DOW and DOY.  This is a good 
reason to use newlib, it has those calculations built into the mktime() 
functions.

For example, I have a TTY menu system to field configure the unit.  This 
is a snippet of taking an ASCII time string ("HH:MM:SS YYYY:mm:DD") into 
a unix epoch (via recordTimeStuff()), then setting the clock via newlib 
setttimeofday():

========== begin menu func =================

time_t timeNow;
char strResult[64];

void setClockTime (const action_params_t * param)
{
struct timeval newTime;
   newTime.tv_sec = timeNow;
   newTime.tv_usec = 0;
   settimeofday(&newTime, 0);
}

static bool extractTimeInfo (void)
{// return True if something went wrong.
struct tm nowTime;
char  *  ptr;
      // extract hours.
   if ((ptr = strtok(strResult, ":")) == NULL) return True;
   nowTime.tm_hour = atoi(ptr);
   if ((nowTime.tm_hour < 0) || (nowTime.tm_hour > 23)) return True;
      // extract minutes.
   if ((ptr = strtok(NULL, ":")) == NULL) return True;
   nowTime.tm_min = atoi(ptr);
   if ((nowTime.tm_min < 0) || (nowTime.tm_min > 59)) return True;
      // extract seconds.
   if ((ptr = strtok(NULL, " ")) == NULL) return True;
   nowTime.tm_sec = atoi(ptr);
   if ((nowTime.tm_sec < 0) || (nowTime.tm_sec > 59)) return True;
      // extract year.
   if ((ptr = strtok(NULL, "-")) == NULL) return True;
   nowTime.tm_year = (atoi(ptr)-1900);
   if ((nowTime.tm_year < 0) || (nowTime.tm_year > 137)) return True;
      // extract month.
   if ((ptr = strtok(NULL, "-")) == NULL) return True;
   nowTime.tm_mon = (atoi(ptr))-1;
   if ((nowTime.tm_mon < 0) || (nowTime.tm_mon > 200)) return True;
      // extract day.
   if ((ptr = strtok(NULL, " ")) == NULL) return True;
   nowTime.tm_mday = atoi(ptr);
   if ((nowTime.tm_mday < 0) || (nowTime.tm_mday > 200)) return True;
     // create unix epoch.
   timeNow = mktime(&nowTime);
   return False;
}

static void recordTimeStuff (void)
{// just parse into time_t for now, will SET later.
   if (extractTimeInfo()) {
      emitErrorPrompt(eStrBadTimeDateValue);
   }
}
============== snip ====================


This is the newlib stub I wrote to settimeofday():


============ begin setttimeofday ===========
int settimeofday (const struct timeval * newDate, const struct timezone 
* tz)
{
struct tm newTime;
time_t epochTime = newDate->tv_sec;
      // convert from unix seconds into discrete time elements.
#ifdef HAS_CLOCK
   localtime_r(&epochTime, &newTime);
   newTime.tm_year += 1900;
   newTime.tm_mon += 1;
   newTime.tm_yday += 1;
   writeRTC (&newTime);
#endif
   return 0;
}
============ snip =====================



TomW

-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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