[sci.electronics] Accurate Real Time Clock Needed!

slewissj@cc.curtin.edu.au (Stephen J Lewis) (06/07/91)

Hi All,

	I am in desperate need of an accurate Real Time Clock for
	a project I am working on. It needs to be accurate to
	within 1 second a day, and I can't seem to find any crystals or
	oscillators that are accurate enough to run any standard RTCs,
	so I am looking for an RTC that has an onboard oscillator 
	(accurate to within 1 sec/day), can be easily accessed on a 
	microprocessor bus as well as be easily battery backed up.

	I don't ask for much!

	If anyone can help me I would greatly appreciate it.

				Thanks In Advance

					Steve.

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Disclame:- I take no responsibility for anything! That includes my spelling!
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rogerm@hpfcso.FC.HP.COM (Roger Mitchell) (06/08/91)

Try the Epson RTC-58321 chip. It has a built in crystal and is accurate to 
less than 1 minute per year.
			Roger M
			N0MCR

nickolas@cpsc.ucalgary.ca (Nickolas Chondropoulos) (06/08/91)

I'm not sure if this would do the trick but look into the DS1216E by Dallas 
Semiconductor.  It is a 28 pin Smartwatch and can sit under any ROM on the bus.
It is accurate to 1 sec/month, good for a century and has a lithium battey built
in that lasts for 10 years.  Usual price up here in Calgary is ~$35.00 CAN.

Nick.

hamid@uop.uop.edu (Mohd H Misnan) (06/08/91)

rogerm@hpfcso.FC.HP.COM (Roger Mitchell) writes:

>Try the Epson RTC-58321 chip. It has a built in crystal and is accurate to 
>less than 1 minute per year.
>			Roger M
>			N0MCR

Does anybody know where can I find the schematic diagram for RTC-58321?
I've the chip but don't have the schematic diagram. Thanks for any help.

-mid-

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