5 INTERRUPT CONTROLLER (ITC)
S1C17M20/M21/M22/M23/M24/M25
Seiko Epson Corporation
5-1
TECHNICAL MANUAL (Rev. 1.0)
5 Interrupt Controller (ITC)
5.1 Overview
The features of the ITC are listed below.
• Honors interrupt requests from the peripheral circuits and outputs the interrupt request, interrupt level and vector
number signals to the CPU.
• The interrupt level of each interrupt source is selectable from among eight levels.
• Priorities of the simultaneously generated interrupts are established from the interrupt level.
• Handles the simultaneously generated interrupts with the same interrupt level as smaller vector number has high-
er priority.
Figure 5.1.1 shows the configuration of the ITC.
CPU core
ITC
Watchdog timer
Interrupt request
Interrupt level
Vector number
Internal reset signal
Debug interrupt
HALT/SLEEP
cancelation signal
Interrupt request
NMI
ILVx[2:0]
Interrupt
control
circuit
ILVy[2:0]
Interrupt request
• • •
• • •
Peripheral circuit
Peripheral circuit
Inter
nal data
bu
s
Figure 5.1.1 ITC Configuration
5.2 Vector Table
The vector table contains the vectors to the interrupt handler routines (handler routine start address) that will be
read by the CPU to execute the handler when an interrupt occurs.
Table 5.2.1 shows the vector table.
Table 5.2.1 Vector Table
TTBR initial value = 0x8000
Vector number/
Software interrupt
number
Vector address Hardware interrupt name
Cause of hardware interrupt
Priority
0 (0x00)
TTBR + 0x00 Reset
• Low input to the #RESET pin
• Power-on reset
• Key reset
• Watchdog timer overflow
*
2
• Supply voltage detector reset
1
1 (0x01)
TTBR + 0x04 Address misaligned interrupt Memory access instruction
2
–
(0xfffc00)
Debugging interrupt
brk instruction, etc.
3
2 (0x02)
TTBR + 0x08 NMI
Watchdog timer overflow
*
2
4
3 (0x03)
TTBR + 0x0c Reserved for C compiler
–
–