GTA02 Power Glitch Reason Found
andy at openmoko.com
Tue Feb 5 09:23:48 CET 2008
-----BEGIN PGP SIGNED MESSAGE-----
Hi folks -
VB_SYS has no decoupling at all on our design. In the Application
Information diagram on p97 of the NXP data, it requires 10uF. I added a
1uF I had lying around and it improves the signal as you would expect.
This net experiences a great deal of glitching and noise from the
missing decoupling, an example during boot is attached (which didn't
crash the thing!). This will easily explain all the crazy shutdown
This is a real problem that is going to require manual rework before
ship, but that should be possible neatly from the VB_SYS end of the
recently added 10K resistors for EXTON[1..3] to 0V on C1764.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org
-----END PGP SIGNATURE-----
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 98086 bytes
Desc: not available
Url : http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080205/d425b20b/attachment.jpg
More information about the openmoko-kernel