125
5.4.5
Interrupt Response Times
The H8S/2345 Series is capable of fast word transfer instruction to on-chip memory, and the
program area is provided in on-chip ROM and the stack area in on-chip RAM, enabling high-
speed processing.
Table 5.9 shows interrupt response times - the interval between generation of an interrupt request
and execution of the first instruction in the interrupt handling routine. The execution status
symbols used in table 5.9 are explained in table 5.10.
Table 5.9
Interrupt Response Times
Normal Mode
*
5
Advanced Mode
No.
Execution Status
INTM1 = 0
INTM1 = 1
INTM1 = 0
INTM1 = 1
1
Interrupt priority determination
*
1
3
3
3
3
2
Number of wait states until executing
instruction ends
*
2
1 to
19+2·S
I
2·S
K
S
I
2·S
I
2
1 to
19+2·S
I
3·S
K
S
I
2·S
I
2
1 to
19+2·S
I
2·S
K
2·S
I
2·S
I
2
1 to
19+2·S
I
3·S
K
2·S
I
2·S
I
2
3
PC, CCR, EXR stack save
4
Vector fetch
5
Instruction fetch
*
3
6
Internal processing
*
4
Total (using on-chip memory)
Notes: 1. Two states in case of internal interrupt.
2. Refers to MULXS and DIVXS instructions.
3. Prefetch after interrupt acceptance and interrupt handling routine prefetch.
4. Internal processing after interrupt acceptance and internal processing after vector fetch.
5. ZTAT, mask ROM, and ROMless versions only.
11 to 31
12 to 32
12 to 32
13 to 33
Table 5.10
Number of States in Interrupt Handling Routine Execution Statuses
Object of Access
External Device
8 Bit Bus
16 Bit Bus
Symbol
Internal
Memory
2-State
Access
3-State
Access
2-State
Access
3-State
Access
Instruction fetch
S
I
S
J
S
K
1
4
6+2m
2
3+m
Branch address read
Stack manipulation
Legend
m
: Number of wait states in an external device access.