Mitsubishi Q02CPU

9
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9.6 Index Register (Z)
9.6.1 Switching between scan execution and low speed execution types
9
DEVICE EXPLANATION
9.6.1 Switching between scan execution and low speed execution types
Note13
The CPU module saves (protects) and restores the index register (Z0 to 15) contents
when switching between a scan execution type program and a low speed execution type
program.
(1) When switching from a scan execution type program to a low speed
execution type program occurs.
The CPU module saves the index register value of the scan execution type program
and restores the index register value of the low speed execution type program.
(2) When switching from a low speed execution program to a scan
execution type program occurs.
The CPU module saves the index register value of the low speed execution type
program and restores the index register value of the scan execution type program.
(3) Exchanges of index register data
Word devices should be used for exchanges of index register data between scan
execution type programs and low speed execution type programs.
Note13
Diagram 9.59 Saving and restoration of index register value at switching between scan and low speed execution type programs
Redundant
Basic
Note9.12
Note9.12
The Basic model QCPU and Redundant CPU cannot use low speed execution type programs.
When the Basic model QCPU or Redundant CPU is used, it is not necessary to be conscious of
the description in this section.
Note9.12
Redundant
Basic
Execution program
Index register value
Index
register
storage
area
For scan execution
type programs
For low speed
execution type
program
Scan execution
type program
Low speed
execution type
program
Saved Reset
Saved
Reset Saved Reset
Z0=3
Z0=6
Z0=3
Z0=6
Z0=3
Z0=1
Z0=3
Z0=1
Z0=3
Z0=1
Z0=0
Z0=1
Z0=0
Z0=0
Z0=0
Switching
Scan execution
type program
Low speed
execution type
program
1: For low-speed execution type program, Z0 is changed to 3.
2: For scan execution type program, Z0 is changed to 6.
Z0=1 Z0=0 to Z0=3
1
Switching
Z0=1 to Z0=6
2
Switching