Mitsubishi Q00JCPU User Manual page 510

9
DEVICE EXPLANATION
(2) Index register processing
Execution program
Index register value
Index register storage
area
For scan/low speed
execution type program
Diagram 9.61 Index register saving (protection)/restoration (When "High-speed execution" is not selected)
9
9.6 Index Register (Z)
- 59
9.6.2 Switching scan/low speed exec. to Interrupt/fixed scan exec.
(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.
Scan/low speed
execution type
program
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.
Interrupt
Switching
program/Fixed
scan execution
type program
Transferred
Z0=1 Z0=1 to Z0=3
Saved
Z0=0 Z0=1
: For interrupt program, Z0 is changed to 3.
Scan/low speed
Reset
execution type
program
Reset
Z0=1 Z0=1
Z0=1
Z0=1