[U-Boot-Users] [PATCH] Write DS1306 RTC Seconds First

Alan J. Luse alanl at timeamerica.com
Tue May 2 22:36:24 CEST 2006


> -----Original Message-----
> From: wd at denx.de [mailto:wd at denx.de] 
> Sent: Tuesday, 02 May 2006 12:01 PM
> To: Alan J. Luse
> Cc: u-boot-users at lists.sourceforge.net
> Subject: Re: [U-Boot-Users] [PATCH] Read DS1306 RTC Seconds First 
> In message 
> <5642B638DBEF6A4DBF9E9BC68144866D0276A427 at tamail1.timeamerica.
> com> you wrote:
> >
> > Read DS1306 RTC seconds first to latch reading and maintain 
> integrity.
> Your patch description does not match the  content.  You  talk  about
> reading, but modify the writing code.
> And I think writing the seconds first  is  actually  worse  than  the
> current code. Please explain what you really are trying to fix.
> Best regards,
> Wolfgang Denk


My mistake; there's a Linux driver that does the read backwards and I
got them confused.  Maxim/Dallas does in fact specify that the seconds
should be written first; I quote:

"The internal time and date registers continue to increment during write
operations. However, the
countdown chain is reset when the seconds register is written. Writing
the time and date registers within
one second after writing the seconds register ensures consistent data."

I have reworded the patch description and resubmit it as attached.

Alan J. Luse
Embedded Systems Engineer
Time America, Inc.
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