Samsung S3C2440A - Manual (Page 359)

S3C2440A RISC MICROPROCESSOR INTERRUPT CONTROLLER
14-9
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INTERRUPT MODE (INTMOD) REGISTER
This register is composed of 32 bits each of which is related to an interrupt source. If a specific bit is set to 1, the
corresponding interrupt is processed in the FIQ (fast interrupt) mode. Otherwise, it is processed in the IRQ mode
(normal interrupt).
Please note that only one interrupt source can be serviced in the FIQ mode in the interrupt controller (you should
use the FIQ mode only for the urgent interrupt). Thus, only one bit of INTMOD can be set to 1.
Register Address R/W Description Reset Value
INTMOD 0X4A000004 R/W Interrupt mode regiseter.
0 = IRQ mode 1 = FIQ mode
0x00000000
Note
If an interrupt mode is set to FIQ mode in the INTMOD register, FIQ interrupt will not affect both INTPND and
INTOFFSET registers. In this case, the two registers are valid only for IRQ mode interrupt source.