On Wed, May 6, 2015 at 10:23 AM, Scott Ellis <[email protected]> wrote: > I'm working on a project where we want a touchscreen always > attached (inside a case), but with the option of using an HDMI > attached monitor when it's available. > > The problem is the HDMI isn't working if the touchscreen > board is also attached. > > We are not trying to hot-plug. Changing the display doesn't > happen often, so we are fine rebooting, loading a different dtb > for the touchscreen or HDMI. (A script modifies uEnv.txt). > > Here's is what works: > > 1) HDMI plugged in, touchscreen plugged in, loading touchscreen dtb, > touchscreen works > > 2) No HDMI plugged in, touchscreen plugged in, loading touchscreen dtb, > touchscreen works > > 3) HDMI plugged in, no touchscreen plugged in, loading hdmi dtb, hdmi works > > What doesn't work: > > 4) HDMI plugged in, touchscreen plugged in, loading hdmi dtb, NO hdmi > > > I get the same behavior plugging a BBB into with 3 different touchscreen > boards (4D 7.0 LCD Cape, NewHaven 5.0 Cape, custom board) > > If I have an HDMI attached, loading hdmi dtb, the BBB HDMI works fine. > > If I boot the very same system, but now with a touchscreen also plugged > in, there is no HDMI output. > > First off, should this be working?
'should'... It's "possible" only if the touchscreen lcd and hdmi share the exact same video parameters, because in essence that is what your doing.. Sharing "1" lcd output between "2" devices. If you truly want two separate displays, this is NOT the board for you... Regards, -- Robert Nelson https://rcn-ee.com/ -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
