Fwd: Suspend mode measuring

Wolfgang Spraul wolfgang at openmoko.com
Thu Feb 7 19:33:13 CET 2008


fyi

Begin forwarded message:

> From: Werner Almesberger <werner at openmoko.org>
> Date: February 8, 2008 2:09:28 AM GMT+08:00
> To: Andy Green <andy at openmoko.com>
> Cc: ALLEN_CHANG at fic.com.tw, matt_hsu at openmoko.org,  
> TIM_LEE at fic.com.tw, wolfgang at openmoko.com, TONY_TU at fic.com.tw,  
> Samuel Ortiz <sameo at openedhand.com>
> Subject: Re: Suspend mode  measuring
>
> Andy Green wrote:
>> 2) I looked at other SDIO designs and they do not pull up the SD /  
>> SDIO
>> clock line.  Can make R7909 NC?
>
> Having a pull-up on the clock definitely sounds like a bug, yes.
>
>> 3) R1710 / R1741 is a bit of a strange pair.  R1741 should be NC?   
>> Or is
>> there a bigger story there?
>
> I think the story goes like this: ultimately, we would have liked to
> have a (very weak) pull-down there, so that we can use KEEPACT to
> signal that the CPU have come out of reset and is in charge.
>
> R1710 is only there to make KEEPACT work until we've implemented and
> tested the software side of it.
>
> However, if we're going to drop that functionality anyway, we should
> remove R1741 and probably also make R1710 a bit larger. KEEPACT leaks
> up to 1uA, so 100kOhm for R1710 would be perfect.
>
> - Werner

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