VGA Consumer II interrupt

alberto239955 · ‎2003-07-17

Posted on July 18, 2003 at 06:13

alberto239955 · ‎2003-07-15

Posted on July 15, 2003 at 21:46

What is the vector number for the VGA vertical retrace interrupt. What is the sequance of operation for VGA register to use it?

Many thanks in advance

Alberto Magnani

thierry239955_st · ‎2003-07-15

Posted on July 16, 2003 at 06:26

Alberto,

The VGA interrupt is not routed to the PIC inside the STPC and the only way to generate interrupts is to connect the vertical synchro pin of the VGA output to one of the ISA IRQs, or to a GPIO or anything else which generate interrupts.

You could also try to use the synchro signal of the TFT interface. With this signal, you can adjust the interrupt edge at one horizontal line level of accuracy.

Farfalla

[ This message was edited by: Farfalla on 16-07-2003 10:12 ]

alberto239955 · ‎2003-07-15

Posted on July 16, 2003 at 07:17

I have seen that there is already a flip-flop inside to catch the sync and store until reset, but do you know what is the register sequance to use it? I have tried following the manual, and the result is that the flip-flop is triggered casually.

Any Idea?

Many thanks for the previous answer.

Alberto Magnani

thierry239955_st · ‎2003-07-17

Posted on July 18, 2003 at 06:02

I don't know... but these registers are VGA compatible. Maybe you can find informations in a book concerning VGA and also try the same software in another x86 platform to verify it is not a behaviour specific to the STPC.

Farfalla

alberto239955 · ‎2003-07-17

Posted on July 18, 2003 at 06:13

Yes , it's specific.