
18 INTERRUPT CONTROLLER
S1C38000 TECHNICAL MANUAL
EPSON
171
18 Interrupt Controller
18.1 Overview
The Interrupt Controller (INTC) handles two Fast Interrupt Request (FIQ) and 32 normal Interrupt
Requests (IRQ). For a list of the interrupt assignment, please refer to Table 7-3, “Interrupt
Assignment,” on page 84. Except for the external interrupt inputs, all interrupt requests are active
high and level triggered. INT7 can be programmed to use different polarities and level/edge triggers.
The INTC processes the FIQ and IRQ inputs and generates two interrupt request signals, JnFIQ and
JnIRQ to the ARM720T.
No hardware prioritization mode is provided.
18.2 FIQ
The FIQ sources are the interrupt input pin INT7 and Timer 0. These two FIQs are used to generate
the JnFIQ signal to the ARM720T. INT7 corresponds to FIQ0 and Timer 0 to FIQ1.
18.3 IRQ
The IRQ sources come from internal components. All the IRQ interrupts are OR’ed together to
generate the JnIRQ signal to the ARM720T. There are 32 IRQ’s, each corresponds to a bit position
of the 32-bit IRQ registers. For example, bit 0 corresponds to IRQ0, and bit 1 to IRQ1, etc.
IRQ[22:0] are used for internal components while IRQ[31:23] are reserved for future use.
18.4 Register Descriptions
The default base address for the INTC registers is F8000200h. All non-reserved register bits default
to 0 unless specified otherwise.
bits 22–0
IRQ[22:0] Status
Each bit location provides the status of the corresponding interrupt source after
masking. A 1 indicates that the interrupt is active and an interrupt request will be sent to
the processor. The bit locations are as follows:
IRQ Status Register
IRQ[000h]
Default = 0000 0000h
Read Only
n/a
IRQ[22:16] Status
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
IRQ[15:0] Status
15
14
13
12
11
10
9876543210
Bit
Interrupt Source
Bit
Interrupt Source
22
CompactFlash
21
Generic Interface Bus
20
Real Time Clock
19
Reserved
18
USB
17
FIR
16
UART2/SIR
15
UART1
14
PWM
13
SPI2
12
SPI1
11
GPIOB
10
GPIOA
9
DMA
8Timer 4
7
Timer 3
6Timer 2
5
Timer 1
4Timer 0
3
Debug
2
Debug
1
Software Interrupt
0Watchdog Timer