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Posted - 02 Jun 2005 :  18:06:14  Show Profile  Email Poster
Backlight Operation Specification

The specification below describes the backlight driver that is being phased into all current ADS products.

Registry and hardware table entries define and control backlight operation.

VGX 4.20.20 with boot code 1.08
GCX 4.20.10 with boot code 1.03
AGX 4.20.25 with boot code 1.06

Revision History

The following list summarizes the changes in the driver specification. See the spec for full details.
1.1 (Oct-2005) PDF 176kB
- Adds StateForIdle registry key

1.0 (Jun-2005)
- Initial release

Edited by akidder 22-May-2006: Add spec 1.1


133 Posts

Posted - 01 Oct 2010 :  17:25:37  Show Profile  Email Poster
To help expand on the information around our backlight controls, we are quoting below some responses from one of our WinCE experts used on our GCX board, but it applies to many others:

These settings are used to adjust for differences in backlight controllers. Some backlight controllers turn the backlight on when the backlight control is 0V, like the controller in our dev kit, and others turn the backlight off when the voltage is 0V. So if your backlight is on when it should be on, then these settings are correct. If your backlight is off when it should be on, then change the settings.

If you do not want the backlight on while the bootloader runs and the OS loads, then you would want the HWT settings opposite of the REG settings.

1. What does the "backlight level at boot" key do in the adsload.hwt file?

0xA1E30010 0x80000000 ;This value causes the backlight control to be turned on when the bootloader runs
0xA1E30010 0x80000001 ;This value causes the backlight control to be turned off when the bootloader runs

2. What do the following registry key values do?

"StateForOn"=dword:1 ; 1 = Inverted Backlight control, 0 = Normal backlight control
"StateForIdle"=dword:1 ; no effect on GCX

3. When the StateForOn and StateForOff values are set to 1, what should be the state of the output voltage?

With StateForOn set to 1, when the backlight is on, the voltage should be high and when the backlight is off, the voltage should be low.
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