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Re: RTC Trickle Charge Value




----- Original Message ----- 
From: "Dave Matlock" <Dave.Matlock@xxxxxxx.com>
To: <dev-etrax@xxxxxxx.com>
Sent: Wednesday, July 02, 2003 1:32 AM
Subject: RTC Trickle Charge Value


> What value should I use for the DS1302 RTC chip trickle charge in the
kernel configuration?  Is only one of the values valid or do they each have
different functions?
>
> Thanks,
> Dave

It depends on if the backup power source to the DS1302 is rechargable or not
and the maximum charge current for it.
If it's not rechargable use 0.
If it is rechargable you can choose to have 1 or 2 diodes and
2k, 4k or 8k ohm resistor to reduce the charge current.

On a devboard_lx (with capacitor) I suggest: 6
Imax = (3.3v-0.7V)/4kohm = 0.65mA
(changing to 5 giving Imax = (3.3v-0.7V)/2kohm = 1.3mA
 would probably be ok to)

On a devboard_82 (with non-rechargable battery): 0

/Johan