IRQ priorities

Hello!

I am using QNX4 and I am looking into a problem with
serial line overruns. (they just happen on ser4 which uses
irq 9).

Primary PIC priorities are 3,4, … 0, 1, 2. This can be changed
with Proc32 option. But I haven’t found any info about priorities
of secondary PIC. Which irq of 9-15 has the highest priority?
I know, that they all then go to IRQ2.

Thanks,

Pavol Kycina

Pavol Kycina <kycina@microstep-hdo.sk> wrote:

Hello!

I am using QNX4 and I am looking into a problem with
serial line overruns. (they just happen on ser4 which uses
irq 9).

Primary PIC priorities are 3,4, … 0, 1, 2. This can be changed
with Proc32 option. But I haven’t found any info about priorities
of secondary PIC. Which irq of 9-15 has the highest priority?
I know, that they all then go to IRQ2.

On the secondary PIC, 8 is highest, 15 is lowest, and it is not
reconfigurable with anything QNX supplies. (You could probably
talk to the secondary PIC directly and re-configure this, if you
were very careful to ONLY change those particular bits in the
control register(s)… read/modify/write… but this isn’t a
recommended or supported action.)

-David

QNX Training Services
dagibbs@qnx.com

Thanks for the info.

Pavol Kycina


“David Gibbs” <dagibbs@qnx.com> wrote in message
news:93niq7$a8q$1@nntp.qnx.com

Pavol Kycina <> kycina@microstep-hdo.sk> > wrote:
Hello!

I am using QNX4 and I am looking into a problem with
serial line overruns. (they just happen on ser4 which uses
irq 9).

Primary PIC priorities are 3,4, … 0, 1, 2. This can be changed
with Proc32 option. But I haven’t found any info about priorities
of secondary PIC. Which irq of 9-15 has the highest priority?
I know, that they all then go to IRQ2.

On the secondary PIC, 8 is highest, 15 is lowest, and it is not
reconfigurable with anything QNX supplies. (You could probably
talk to the secondary PIC directly and re-configure this, if you
were very careful to ONLY change those particular bits in the
control register(s)… read/modify/write… but this isn’t a
recommended or supported action.)

-David

QNX Training Services
dagibbs@qnx.com