how to disable the 5v output of a serial port?

[039648690]

hi there...

i would realy like to get help on this.
i need to disable the 5v output on the 4 pin of a mouse serial output.i tried to get it done by setting the 4th bit of the 3f8H memory byte to zero and that didn't do the trick.i tried to get this by setting to zero complete bytes of several potential addressess (my pc is still running... ). i got lost here. i would thank any one who will help...

Grupi

 

[Jay1Roy]

Hi Grupi,

Doing what you did once isn't going to keep the state. This level should be reduced to zero whenever there is a change. This can be trapped by hooking up your own Interrupt Service Routine to the mouse interrupt. So your routine overrides the original one and makes this change and hands the control back to the original one for normal functioning.

This type of coding is know as TSR programs. They are Terminate and Stay Resident codes and they start with the function

keep(...);

Refer to manual for function details. This is how drivers and not to mention, viruses are programmed.

Hope this helps... have fun coding.

Roy