[Avila] problems with hwclock on arm (avila board with ixdp425)

[Ron Eisworth]

Jake, thanks for the code fix. 

Just to give a little more info ~ the hwclock function can hang under Linux
if the DS1672 RTC is not initialized (oscillator started). The oscillator is
started when the boards are programmed at the factory. This register can
however be over written by the user's software or the bit can be reset if
the battery goes dead or is shorted momentarily. The oscillator start bit
(EOSC#) is in the DS1672 device control register (on I2C bus). The default
for this bit is a "1" (osc. shutoff) and it must be cleared to a "0" (osc.
on) for the RTC to keep time when power is off. See the Dallas/Maxim DS1672
datasheet for more info: 

http://datasheets.maxim-ic.com/en/ds/DS1672.pdf

This register's function is to reduce the drain on the battery when the unit
is in storage.

Ron Eisworth

-----Original Message-----
From: Jake Farrell [mailto:jake at amperion.com] 
Sent: Tuesday, April 03, 2007 2:29 PM
To: avila at lists.unixstudios.net
Subject: [Avila] problems with hwclock on arm (avila board with ixdp425) 
Subject: [Avila] Sounds like your RTC became disabled. The RTC (i2c bus addr 68) can become
set to enabled or disabled, a quick solution for you would be to set the
control on the clock back to enabled with these lines
i2cset -y 0 0x68 0x0 0xb109 w                
i2cset -y 0 0x68 0x4 0x4612 w
i2cset -y 0 0x68 0x6 0x0000 w