Interrupt Request Register (Irq) - Samsung S3C8275X User Manual

S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X

INTERRUPT REQUEST REGISTER (IRQ)

You can poll bit values in the interrupt request register, IRQ (set 1, DCH), to monitor interrupt request status for all
levels in the microcontroller's interrupt structure. Each bit corresponds to the interrupt level of the same number:
bit 0 to IRQ0, bit 1 to IRQ1, and so on. A "0" indicates that no interrupt request is currently being issued for that
level. A "1" indicates that an interrupt request has been generated for that level.
IRQ bit values are read-only addressable using Register addressing mode. You can read (test) the contents of the
IRQ register at any time using bit or byte addressing to determine the current interrupt request status of specific
interrupt levels. After a reset, all IRQ status bits are cleared to "0".
You can poll IRQ register values even if a DI instruction has been executed (that is, if global interrupt processing
is disabled). If an interrupt occurs while the interrupt structure is disabled, the CPU will not service it. You can,
however, still detect the interrupt request by polling the IRQ register. In this way, you can determine which events
occurred while the interrupt structure was globally disabled.
Interrupt Request Register (IRQ)
DCH, Set 1, Read-only
MSB .7 .6 .5
IRQ5
IRQ6
IRQ7
Figure 5-9. Interrupt Request Register (IRQ)
.4 .3 .2 .1
IRQ1
IRQ2
IRQ3
IRQ4
Interrupt level request pending bits:
0 = Interrupt level is not pending
1 = Interrupt level is pending
INTERRUPT STRUCTURE
.0 LSB
IRQ0
5-13