VGA monitor detecton on DM8168

Chiajung Hsu

Hello :

Some chips has the loading sensor circuit to detect that the montor is connected or disconnected through the 75 ohm double termination on RGB.

Can DM8168 implement this function ?

over 13 years ago

0 HardikShah over 13 years ago

TI__Mastermind 20245 points

Hi,

Unfortunately DM8168 cant implement this function. DM8148 can implement this function.

Regards,

Hardik Shah

0 Chiajung Hsu over 13 years ago in reply to HardikShah

Intellectual 280 points

if DM8168 can't do this , do you know how to implement the monitor detecton through addtiional circuitry ?

0 HardikShah over 13 years ago in reply to Chiajung Hsu

TI__Mastermind 20245 points

Hi,

You can refer to following article, where VGA monitor is detected using DDC interface. You can use I2C masters of the DM8168 to implement DDC interface.

Regards,

Hardik Shah

0 HardikShah over 13 years ago in reply to HardikShah

TI__Mastermind 20245 points

Hi,

Forgot to attached link http://pinouts.ru/Video/VGA15_pinout.shtml

Regards,

Hardik shah

0 Steve Clynes over 13 years ago in reply to HardikShah

TI__Mastermind 43875 points

Periodic DDC checking is really the only reliable way.

I have seen some instances where one of the ground connections on the VGA connector is not connected to ground, but pulled high through a 10K resistor and also fed back to a GPIO on the processor. When the monitor is plugged in it will pull the 'stolen ground' down to 0V and the processor can detect this. The down side of this method is that you need to use one of the signal ground returns. The ground returns are really there for signal return so it can affect signal integrity and EMI if you steal any of them.

BR,

Steve

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VGA monitor detecton on DM8168