Maximum resolution is 1280x1024. It could be that your Sharp 1080 display, can’t handle anything the board throws at it. It reads the EDID to pick the resolution. Try hitting reset and see if the SW can get the EDID information from the TV and find a compatible resolution for your TV.
Gerald
Thanks for the response! This is interesting. Is the max 1280x1024 resolution a hardware limitation or a limitation of this brand of Linux (Angstrom)? Also, I have heard that audio is not working over HDMI on BBB yet. Is this true?
Chuck W.
1280x1024 is a limit of the 125MHZ clock the AM3359 can generate. It is not a Linux/Angstrom limitation. It is described in the System Reference Manual
http://circuitco.com/support/index.php?title=BeagleBoneBlack
Audio does indeed work fine on the board. Lack of audio support in the current image is clearly communicated here.
http://circuitco.com/support/index.php?title=Updating_The_Software
If all goes to plan, sometime early this week the updated image will be made available with audio support and we will be moving to that at the same time as the production image that ships with future board shipments. As expected, audio support will be limited to CEA resolutions as the specifications define. Monitors support audio only at the CEA resolutions which are HDMI. The other supported resolutions are basically DVI-D which does not support audio.
Gerald
Ok - thanks for the information. I’m still working on the video over HDMI on this TV. The TV still didn’t recognize the BBB over HDMI after a reset. I’ll look up this TV and find out which resolutions it supports and then edit the xserver config file to match. Either that or try Ubuntu. I’ll keep trying things until it works. I’ll post what I find.
Chuck W.
1280x720 should work. You could try the candidate release that is coming out and give it a shot. It has the audio and should default to 1280x720.
http://dominion.thruhere.net/koen/angstrom/beaglebone/BBB-eMMC-flasher-2013.05.03.img.xz
Gerald
Great! Thanks for the link. I’m downloading the new image now and will post results after testing it out.
Chuck W.
Still no luck. I installed the new image to the BBB onboard memory and that works well. I am able to edit the xorg.conf file with settings for my TV (1280x1024_60) and restart but nothing changes. I’m not sure where to go from here. Any suggestions would be appreciated.
Here’s my xorg.config:
root@beaglebone:~# nano /etc/X11/xorg.conf
GNU nano 2.2.5 File: /etc/X11/xorg.conf
Section “Module”
Load “extmod”
Load “dbe”
Load “glx”
Load “freetype”
Load “type1”
Load “record”
Load “dri”
EndSection
Section “Monitor” $
Identifier “Builtin Default Monitor”
HorizSync 31.5-75
VertRefresh 60
EndSection
Section “Device”
Identifier “Builtin Default fbdev Device 0”
Driver “fbdev”
EndSection
Section “Screen”
Identifier “Builtin Default fbdev Screen 0”
Device “Builtin Default fbdev Device 0”
Monitor “Builtin Default Monitor”
DefaultDepth 24
SubSection “Display”
Depth 24
Modes “1280x1024_60.00”
EndSubSection
EndSection
Section “ServerLayout”
Identifier “Builtin Default Layout”
Screen “Builtin Default fbdev Screen 0”
EndSection
After more investigation I found out about the uEnv.txt file on the BBB. My understanding is this file sets boot arguments, including video resolution.
I added these settings and crossed my fingers:
optargs=quiet
dvimode=1280x1024MR-16@60
defaultdisplay=tv
vram=12MB
It’s still not showing video over HDMI though. 
Chuck W.
Except, dvimode/defaultdisplay/vram all relate to the old "omapfb"
dss2 driver found on the BeagleBoard/PandaBoard.. The BeagleBone
Black has a Davanci based video display (which has different boot
variables) and also in v3.8.x has been converted to KMS which has a
completely different set too.. Which i don't have a reference for at
this time..
Basically, it relies completely on being able to read the monitor's edid..
Regards,
That’s good to know. I am going to try updating the firmware on my TV. Perhaps then the BBB will detect the EDID. If that doesn’t work then I’m out of ideas and will probably return the board to the vendor. Oh well.
Where did you buy the board?
Gerald
I bought it from adaFruit.
Thanks!
Do you have another monitor or TV you can try it on?
Before you return it, do RMA request.
http://beagleboard.org/support/rma
Gerald
No - this is the only TV/computer monitor in the house. I’m keeping my fingers crossed on the firmware update. If that doesn’t work I’ll use the link provided for an RMA request. Thank you for your assistance with this issue.
Chuck W.
I read the through manual. Not much information in it. Some displays have an over scan option that can mess things up. I didn’t see anything in the manual about it. It has a PC interface, so I suspect that the display expects that to be used for a PC, not a HDMI port. I din’t see any resolutions other than 1080. I searched on 1280x720, but didn’t get any hits. Sounds like this display is a single resolution display under HDMI, which is odd.
I would go ahead and try all of the ports to see if one of them may work for you.
Gerald
On page 15 there is a chart of supported resolutions for HDMI. This one is listed: 1280x1024 HFreq: 64kHz VFreq: 60Hz.
Chuck W.
You are correct. I read that as the PC port and missed the HDMI above it. Try a couple of other ports. If it doesn’t work, go ahead and submit the RMA.
Gerald
Still couldn’t get it work, so I’ll RMA the board. The raspberry Pi has no problems on this TV…
Darn, I was excited about this board.
Chuck W.
Just do the RMA. You will be taken care of.
Gerald
RMA sent. Thanks again.