QNX Interrupts for X86

QNX DEVELOPERS Realtime and Embedded
#1

hello,

I want to generate interrupts using the timer(Vector 08h) and handle them by my own Interupt Vector Handler.
How can i do that ? Is it allowed ? Doing a Software Interrupt or a Hardware Interrupt ??

I would apreciate a quick and fast response on the same. Any links with information will also be useful.

Thanks

#2

You can attach an interrupt handler to the timer interrupt, see the documention for writing an interrupt handler at
qnx.com/developers/docs/6.3. … ndler.html

#3

Thanks … i will definitely read the documentation.

cause you said “attach” … i have a quick question to the same. Is it true that when i define a IVH for an interrupt and when an interrupt happens does it call the original IVH which in turn calls my defined IVH unlike DOS where if an interrupt happens it only calls the user defined IVH.

Thanks
ashu

#4

Yes, your interrupt handler is not actually used as the vector handler, that is a part of the os kernel. Rather, there is a list of interrupt handler
routines that must be called.

So you can actually have more than one interrupt handler attached to an interrupt.

#5

How could i trigger an interrupt using the timer and then handle it using my code AND also not affect the system time at all ???

#6

The hardware is responsible of triggering the interrupt. On QNX6 the timer is preprogram to system tick size. You should play with the timer hardware …

If your interrupt routine is short there will be no effect on system time.

#7

well what im trying to do is to increase the clock frequency so as to generate more interrupts

ashu

#8

See other post.