
S3C3410X RISC MICROPROCESSOR
INTERRUPT CONTROLLER
11-5
INTERRUPT PENDING REGISTER (INTPND)
In CPU core, there is PSR(Processor Status Register) register, which has several field including the interrupt
relating I-Flag and F-Flag. As mentioned above, the CPU can accept two kinds of interrupt even if there are
many interrupt sources in S3C3410X. That is why all interrupt sources in S3C3410X should be categorized into
two mode, which is IFQ mode and FIQ mode. In this case, if CPU is running the service for certain interrupt, and
if this interrupt has IRQ mode, the other interrupt sources with IRQ mode can not be serviced until the completion
of current service. These interrupt should be pending in IPR(Interrupt Pending Register). In case of FIQ mode,
other FIQ interrupt request can not take CPU while the current FIQ service is running as same as IRQ case.
Therefore, the FIQ interrupt request should be pending in IPR as same as IRQ. If IRQ interrupt service is
running, the FIQ interrupt can take the CPU for service because FIQ has higher priority than IRQ. In other word,
ARM CPU can support two level interrupt architecture. The pending interrupt service can start whenever the I-
Flag or F-Flag should be cleared to "0". The service routine should clear the pending bit, also.
Register
Offset
Address
R/W
Description
Reset
Value
INTPND
0xc004
R/W
Interrupt pending register.
Indicates the interrupt request status of each source.
0 = The interrupt has not been requested
(when reading)
0 = Clear pending bit (when writing)
1 = The interrupt source has asserted the interrupt
request (when reading)
1 = No effect, keeping current status, '0' or '1'.
(when writing)
0x0
INTPND
Bit
Description
Initial State
EINT0
[0]
0 = Not requested
1 = Requested
0
EINT1
[1]
0 = Not requested
1 = Requested
0
INT_URX
[2]
0 = Not requested
1 = Requested
0
INT_UTX
[3]
0 = Not requested
1 = Requested
0
INT_UERR
[4]
0 = Not requested
1 = Requested
0
INT_DMA0
[5]
0 = Not requested
1 = Requested
0
INT_DMA1
[6]
0 = Not requested
1 = Requested
0
INT_TOF0
[7]
0 = Not requested
1 = Requested
0
INT_TMC0
[8]
0 = Not requested
1 = Requested
0
INT_TOF1
[9]
0 = Not requested
1 = Requested
0
INT_TMC1
[10]
0 = Not requested
1 = Requested
0
INT_TOF2
[11]
0 = Not requested
1 = Requested
0
INT_TMC2
[12]
0 = Not requested
1 = Requested
0
INT_TOF3
[13]
0 = Not requested
1 = Requested
0
INT_TMC3
[14]
0 = Not requested
1 = Requested
0
INT_TOF4
[15]
0 = Not requested
1 = Requested
0
INT_TMC4
[16]
0 = Not requested
1 = Requested
0
INT_BT
[17]
0 = Not requested
1 = Requested
0