using port 21h to mask/unmask interrupts doesn't seem to do that. My routine just masks IRQ 1 and then polls for data, it works fine when I don't type too quickly.

Any ideas?
Posted on 2004-11-02 09:13:35 by vandenab
using port 21h to mask/unmask interrupts doesn't seem to do that. My routine just masks IRQ 1 and then polls for data, it works fine when I don't type too quickly.

Any ideas?


It depends on a few things. First you also need to use A1h for IRQ's 8-15. Second if you are under an OS it might be using the APIC so masking 21h and A1h won't do anything.
Posted on 2004-11-02 15:04:48 by mark_larson
I just want to mask IRQ1, which is bit 1 of the master slave (port 21h). In that sens, I don't need to mask anything on the slave PIC (port A1h).

While reviewing all the I/O hardware resources of my computer, I see no APIC, but three PICS at ports 0x0020 - 0x003F, 0x00A0 - 0x00BF, 0x04D0 - 0x04D1. This is contradictory to anything I read.

By the way, what's an APIC?

Thanks for your help.

Nico.
Posted on 2004-11-03 01:48:26 by vandenab