Mitsubishi Q02CPU

9
- 59
9.6 Index Register (Z)
9.6.2 Switching scan/low speed exec. to Interrupt/fixed scan exec.
9
DEVICE EXPLANATION
(2) Index register processing
(a) When "High-speed execution" is not selected
1) When switching from scan/low speed execution type program to
interrupt/fixed scan execution type program
The CPU module saves the index register value of the scan/low speed
execution type program and passes it to the interrupt/fixed scan execution
type program.
2) When switching from interrupt/fixed scan execution type program to
scan/low speed execution type program
The CPU module restores the saved index register value.
POINT
Word devices should be used to transfer index register data from an interrupt or
fixed scan execution type program to a scan or low speed execution type
program.
Diagram 9.61 Index register saving (protection)/restoration (When "High-speed execution" is not selected)
Execution program
Index register value
Index register storage
area
For scan/low speed
execution type program
Z0=1
Z0=0 Z0=1
Transferred
Switching
Scan/low speed
execution type
program
Saved
Interrupt
program/Fixed
scan execution
type program
Reset
Scan/low speed
execution type
program
Reset
Z0=1 Z0=1 Z0=1
Z0=1Z0=1 to Z0=3
: For interrupt program, Z0 is changed to 3.