migrating LCD from BB-C4 to BB-XM (J4/J5 vs. P11/P13)

GoogleGroups
1

Thanks to recent help, we now managed to merge and
add our own drivers to the new U-Boot for the BB-XM
based on

http://gitorious.org/beagleboard-validation/u-boot/commits/validation-20100818

Now, we have a single SD card image that
boots on a C4 board as well as on the XM.

Just one problem is that we don't see 3.3V on the (new)
LCD connector (renamed from J5 to P13) on the
BB-XM while it is available on the BB-C4.

Do I understand section 8.8.10 EXP_VDD correctly, that
the 3.3V of the C4 board is no longer 3.3V from a separate
LDO but adjustable between 2.5 to 3.0V since it is
VAUX1.OUT of the TPS65950? And can be switched
on/off?

Nikolaus

2

Your understanding is correct. There was design change on the -xM. We no longer provide 3.3V, but we do provide 3.0V form the power management chip. It needs to be turned on to enable it. The issue we had on the -xM was that the 3.3V did not provide enough power on that rail and it was tied to other devices. So, this gave us more flexibility and more current.

Gerald