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Rev.1.10 Jul 01, 2005 page 63 of 318
REJ09B0124-0110
M16C/6N Group (M16C/6NK, M16C/6NM) 9. Interrupt
Under development
This document is under development and its contents are subject to change.
Figure 9.2 Interrupt Vector
9.4.1 Fixed Vector Tables
The fixed vector tables are allocated to the addresses from FFFDCh to FFFFFh. Table 9.1 lists the fixed
vector tables. In the flash memory version of microcomputer, the vector addresses (H) of fixed vectors are
used by the ID code check function. For details, refer to 20.2 Functions to Prevent Flash Memory from
Rewriting.
Table 9.1 Fixed Vector Tables
9.4 Interrupts and Interrupt Vector
One interrupt vector consists of 4 bytes. Set the start address of each interrupt routine in the respective
interrupt vectors. When an interrupt request is accepted, the CPU branches to the address set in the
corresponding interrupt vector. Figure 9.2 shows the interrupt vector.
Low-order address
Middle-order address
Vector address (L)
Vector address (H)
0 0 0 0
0 0 0 0 0 0 0 0
MSB LSB
High-order address
Interrupt Source
Vector table Addresses
Reference
Address (L) to Address (H)
Undefined Instruction (UND instruction) FFFDChto FFFDFh M16C/60, M16C/20 Series Software
Overflow (INTO instruction) FFFE0h to FFFE3h Manual
BRK Instruction
(2)
FFFE4h to FFFE7h
Address Match FFFE8h to FFFEBh 9.10 Address Match Interrupt
Single Step
(1)
FFFECh to FFFEFh
Oscillation Stop and Re-oscillation Detection, FFFF0h to FFFF3h 7. Clock Generating Circuit
Watchdog Timer 10. Watchdog Timer
________
DBC
(1)
FFFF4h to FFFF7h
_______
NMI FFFF8h to FFFFBh
_______
9.7 NMI Interrupt
Reset FFFFCh to FFFFFh 5. Reset
NOTES:
1. Do not normally use this interrupt because it is provided exclusively for use by development support
tools.
2. If the contents of address FFFE7h is FFh, program execution starts from the address shown by the
vector in the relocatable vector table.
9.4.2 Relocatable Vector Tables
The 256 bytes beginning with the start address set in the INTB register comprise a relocatable vector
table area. Table 9.2 lists the relocatable vector tables. Setting an even address in the INTB register results
in the interrupt sequence being executed faster than in the case of odd addresses.