<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=big5">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7650.28">
<TITLE>RE: Suspended mode</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/plain format -->
<BR>
<P><FONT SIZE=2>Hi Andy:<BR>
<BR>
Thanks for your finding.<BR>
In GTA01, TX_MODEM and console_TX use the same UART port(S3C2410).<BR>
Therefore, R1519 use to reduce noise on console.<BR>
Now, I will remove R1519 in GTA02 because it's unused.<BR>
I will remove it to test the 2V on GSM VBAT.<BR>
<BR>
Best Wishes<BR>
Allen Chang<BR>
<BR>
-----Original Message-----<BR>
From: Andy Green [<A HREF="mailto:andy@openmoko.com">mailto:andy@openmoko.com</A>]<BR>
Sent: 2008/2/8 [星期五] 上午 12:33<BR>
To: ALLEN_CHANG (張吉隆)<BR>
Cc: matt_hsu@openmoko.org; openmoko-kernel@lists.openmoko.org; TIM_LEE (李國平經理); TONY_TU [塗能宇專案經理]; werner@openmoko.org; DKAY_CHEN [陳南廷]<BR>
Subject: Re: Suspended mode<BR>
<BR>
-----BEGIN PGP SIGNED MESSAGE-----<BR>
Hash: SHA1<BR>
<BR>
Somebody in the thread at some point said:<BR>
> Hi Andy:<BR>
><BR>
>> Also check all the supply rails like V-DBB, V-IO, V-FLASH (hmm),<BR>
>> V_SRAM, V-SIM, V_RTC (hmm) and V-ABB to find ones that have >=1.8V<BR>
>> in suspend, then try to remove any pullup to these rails, eg, if<BR>
>> V-SIM has >= 1.8V, try to remove R1010 as a test.<BR>
><BR>
> I power off GSM modem and set RX, TX, CTS, and RTS to output Low. The<BR>
> VBAT is 0.004. V-DBB, V-IO, V-FLASH,V-SRAM,V-SIM,V-RTC,and V-ABB are<BR>
> almost zero. I found total current is 4~5mA. It is better than before<BR>
> (8~9mA).<BR>
<BR>
Hi Allen -<BR>
<BR>
In my travels trying to understand another problem I came across R1519<BR>
on the CPU schematic -- it pulls TX_MODEM up by 10K to 3.3V.<BR>
<BR>
Do we really need this? We can save <=330uA if the GSM stuff is powered<BR>
down by removing it. Hey it sounds like nothing but it is up to 6% of<BR>
that 5mA suspend current.<BR>
<BR>
Plus it can be source of the 2V on GSM Vdd you were trying to track down?<BR>
<BR>
- -Andy<BR>
-----BEGIN PGP SIGNATURE-----<BR>
Version: GnuPG v1.4.7 (GNU/Linux)<BR>
Comment: Using GnuPG with Fedora - <A HREF="http://enigmail.mozdev.org">http://enigmail.mozdev.org</A><BR>
<BR>
iD8DBQFHqzLiOjLpvpq7dMoRAl61AJ4yfIOYVveIlmArA8R18C+CpwGilwCcCxXp<BR>
e11VuXJa1DtKt8hlR9gdw38=<BR>
=yHin<BR>
-----END PGP SIGNATURE-----<BR>
<BR>
</FONT>
</P>
</BODY>
</HTML>