Video Interfaces
EPM-19 Hardware Reference Manual
41
Enabling Synchronous Display Output
The BIOS allows for enabling synchronous display outputs. When Synchronous Display is set to
Enabled (disabled by default), the same video signal is present on both the J8 VGA (“CRT” per
the Graphic Utility) connector as well as the J15 LVDS (“LCD” per the Graphic Utility)
connector. The resolution setting must be 1024x768 or lower for the desktop to be displayed
properly on the VGA monitor and it should be optimized for the LCD display in use. This
limitation exists because both outputs share the same video memory contents, so the LCD panel
timing and resolution has to be prioritized (as it is much less flexible than a VGA monitor that
often handles various timings and resolutions).
To change from a synchronous display setup (VGA CRT connected to J8 and a flat-panel display
connected to J15) to a VGA-only configuration, follow these steps:
1.
Leave both display devices connected.
2.
Use the BIOS Setup utility to change the Synchronous Display option from Enabled to
Disabled. Save the changes and exit the BIOS Setup utility.
3.
Reboot the board and allow the operating system to load. A video signal will be present
on the VGA during BIOS loading, but the video signal switches to the LCD panel output
after POST (as the OS loads since LCD was the previous OS setting).
4.
In the video driver Graphic Utility, select the CRT output (instead of the LCD output),
apply that setting, and exit the program.
5.
Power down the board and disconnect the flat-panel display from connector J15 (if the
option is no longer desired).
6.
Power up the board. Use the BIOS Setup utility to set the Boot Display Device to either
VBIOS or CRT if it is set for a Panel #, then save the changes and exit the BIOS Setup
utility. The board will then reboot and the video output will be present on the VGA
CRT.
