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author | Nick Spence <nick.spence@freescale.com> | 2008-08-22 23:52:50 -0700 |
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committer | Kim Phillips <kim.phillips@freescale.com> | 2008-09-03 16:06:46 -0500 |
commit | d9fe88173cb4f7d293796ffe10c7a0d3d426d8f9 (patch) | |
tree | 1e41ed69bee55104040500de9cbfd8f86bc896c6 /doc/README.commands | |
parent | 628ffd73bcff0c9f3bc5a8eeb2c7455fe9d28a51 (diff) | |
download | u-boot-imx-d9fe88173cb4f7d293796ffe10c7a0d3d426d8f9.zip u-boot-imx-d9fe88173cb4f7d293796ffe10c7a0d3d426d8f9.tar.gz u-boot-imx-d9fe88173cb4f7d293796ffe10c7a0d3d426d8f9.tar.bz2 |
MPC83XX: Fix GPIO configuration - set gpio level before direction
Set DAT value before DIR values to avoid creating glitches on the
GPIO signals.
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: Nick Spence <nick.spence@freescale.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Diffstat (limited to 'doc/README.commands')
0 files changed, 0 insertions, 0 deletions