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From: Kim Phillips <kim.phillips@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] mpc83xx: set gpio level before direction
Date: Fri, 29 Aug 2008 14:18:17 -0500	[thread overview]
Message-ID: <20080829141817.f8ff4931.kim.phillips@freescale.com> (raw)
In-Reply-To: <1220035045-5261-1-git-send-email-jacmet@sunsite.dk>

On Fri, 29 Aug 2008 20:37:25 +0200
Peter Korsgaard <jacmet@sunsite.dk> wrote:

> Set gpio level register before direction register to inhibit
> glitches on high level output pins.
> 
> Dir and data gets cleared at powerup, so high level output lines see
> a short low pulse between setting the direction and level registers.
> 
> Issue was seen on a new board with the nReset line of the NOR flash
> connected to a GPIO. Setting the direction register puts the NOR flash
> in reset so the next instruction to set the level cannot get executed.
> 
> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
> ---

Hi Peter,

this is a duplicate of:

http://www.nabble.com/-U-Boot---PATCH--MPC83XX%3A-Fix-GPIO-configuration-to19119329.html#a19119329

so I'll merge your better description and s-o-b to that one if you
don't mind.

Kim

  reply	other threads:[~2008-08-29 19:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-29 18:37 [U-Boot] [PATCH] mpc83xx: set gpio level before direction Peter Korsgaard
2008-08-29 19:18 ` Kim Phillips [this message]
2008-08-29 21:58   ` Peter Korsgaard

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