Searching \ for 'Real Time Clocks' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/timers.htm?key=real+time
Search entire site for: 'Real Time Clocks'.

Truncated match.
PICList Thread
'Real Time Clocks'
1995\11\30@093658 by mfahrion

flavicon
face
Sorry for the lack of pic content - but this is going into a
pic-driven product....

Can anyone recommend a cheap real time clock.  I'm looking for the
basic time/date keeping functions, I have a power budget of a couple
milliamps, and dollar budget of <$5   I could just implement it
into the pic, but that's not going to be practical in this case
unless I can't find an RTC to meet my needs.  Seems like there
should be dozens to choose from that meet those requirements, but in
my first effort search, I'm having almost no luck at all.

Thanks for the help
-mike
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Mike Fahrion          spam_OUTmfahrionTakeThisOuTspambb-elec.com           http://www.bb-elec.com/
B&B Electronics Mfg Co      ph.(815) 433-5100 ext.215    fax (815) 434-7094
707 Dayton Road                     PO Box 1040                           Ottawa
IL 61350
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

1995\11\30@171828 by mike

flavicon
picon face
In message <.....9511301437.aa11806KILLspamspam@spam@punt-4.mail.demon.net> mfahrionspamKILLspambb-elec.com
writes:

Mike,

you might like to look at the Dallas Semiconductor DS1202.

8-pin dip with real time clock (secs, mins, hours, day of month,
month, day of week, and year with leap year compensation) and
24 bytes of static ram. I don't know the price though.

Regards,

Mike Watson

{Quote hidden}

Ottawa
>  IL 61350
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>

--
Mayes uk


'Real Time Clocks'
1995\12\01@043106 by Philippe TECHER
flavicon
face
On Nov 30, mike wrote:

>Can anyone recommend a cheap real time clock.  I'm looking for the
>basic time/date keeping functions, I have a power budget of a couple
>milliamps, and dollar budget of <$5   I could just implement it
>into the pic, but that's not going to be practical in this case
>unless I can't find an RTC to meet my needs.  Seems like there
>should be dozens to choose from that meet those requirements, but in
>my first effort search, I'm having almost no luck at all.


Just try PHILIPS Semiconductor PCF8583 it's also a real time clock as DALLAS
DS1202 with I2C interface, 8-pin dip with real time clock (secs, mins,
hours, day of month, month, day of week, and year with leap year
compensation) and
256 bytes of static ram and also alarm. I already wrote I2C routine for PIC.

As I'm reading the data sheet,
  Current comsumption:   200uA MAX (operating mode)
                          50uA MAX at 5V (clock mode)
  Supply voltage:        2,5V to 6V (I2C bus active)
                         1,0 to 6V  (I2C bus inactive)

US price: don't know ...
PHILIPS US Contact: Phone 800 234-7381
                   Fax   708 296-8556
Regards,
       Philippe.

1995\12\02@001047 by Wynn A. Rostek

flavicon
face
d


'Real Time Clocks'
1999\01\30@113433 by Donald L Burdette
picon face
Several others make real time clock chips.  Check out Epson, Dallas
(http://www.dalsemi.com) and Seiko.

Dallas in particular makes a wide variety of different chips.  Interfaces
for parallel, IIC, 1-Wire, SPI, etc.  They also have some sub-microamp
parts.  The part I buy and use is under $2.00, so it's cheaper than the
PIC, lower power, more accurate, smaller.

Why use a dedicated PIC?

                               Don

1999\01\30@184644 by Peter Tran

flavicon
face
Thank you for helping. I just try to use all resources in 16f84, but I think
it's hard.
----- Original Message -----
From: Donald L Burdette <EraseMEdlburdettespam_OUTspamTakeThisOuTJUNO.COM>
To: <PICLISTspamspam_OUTMITVMA.MIT.EDU>
Sent: Saturday, January 30, 1999 7:07 AM
Subject: Re: Real Time Clocks


{Quote hidden}

________________________________________________________
NetZero - We believe in a FREE Internet.  Shouldn't you?
Get your FREE Internet Access and Email at
http://www.netzero.net/download.html

1999\01\30@195400 by paulb

flavicon
face
Peter Tran wrote:

> I just try to use all resources in 16f84, but I think it's hard.

 Some well-known if not necessarily popular Australian politician (PM
actually) is indelibly remembered for the quote "Life wasn't meant to
be easy".  Most people don't remember much else about him in detail now!

 It all depends on the goal.  If you want to make a clock display, then
first choice is a purpose-built clock chip.  If, that is, one offers
the particular function you *require*.

 If you need a function no such chip offers, or they are substantially
more expensive, then a PIC will certainly do the job.  Such a "novel
function" is http://www.bobblick.com/bob/projects/mclock.html by way of
example.

 Most such clock displays run from mains power and indeed, use this for
timing because for the purpose it is in most parts of the world
*extremely accurate* except for "glitches".  You can use a software
Phase Locked Loop to correct for these though.

 You may however want to rely on battery power and a crystal timebase.
Purpose-designed clock crystals, generally 32,768Hz provide this with
accuracy given some attention to oscillator design.  This is what is
used in your PC.  Higher-frequency (Megahertz) crystals can be trimmed
for timekeeping with varying results.

 The choice now between using the PIC alone, or using a PIC and RTC
chip (because you can't use an RTC chip alone ;-) is based on two
considerations; power consumption and task complexity.  The RTC chip
will most likely use a lot less power than the PIC and the latter can be
made to sleep to save power (certain PICs have of course, RTC function
built-in, but I'm going to ignore that!  Cost is equivalent to PIC plus
RTC in any case).

 Alternately, if the PIC is overall very busy, it may be *much* easier
to write code to leave the timekeeping to the RTC.

 But, if you have a job which requires a PIC but does not make heavy
calls on the processing power of or require timing precision from the
PIC, and you are not trying to conserve battery power, *and* you have a
reasonably accurate crystal driving the PIC then you might as well give
the PIC something useful to do by counting the time which it will most
certainly do perfectly accurately if you write good code.
--
 Cheers,
       Paul B.


'Real Time Clocks'
1999\02\01@052844 by Dr. Imre Bartfai
flavicon
face
Hi,
add Ricoh, too. The RS5C313 does it fine, and cheap.
Imre


On Sat, 30 Jan 1999, Donald L Burdette wrote:

{Quote hidden}

More... (looser matching)
- Last day of these posts
- In 1999 , 2000 only
- Today
- New search...