I/O Instruction Timing - Omron CS1G/H-CPUxx-EV1 Programming Manual

Basic Concepts
2-1-9

I/O Instruction Timing

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Differentiated Instructions
The following timing chart shows different operating timing for individual
instructions using a program comprised of only LD and OUT instructions.
B1
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B3
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B6
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B9
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B10
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B11
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B12
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CPU pro-
cessing
Instruction
I/O refresh
executed.
• A differentiated instruction has an internal flag that tells whether the previ-
ous value is ON or OFF. At the start of operation, the previous value flags
for upwardly differentiated instruction (DIFU and @ instructions) are set to
ON and the previous value flags for downwardly differentiated instructions
(DIFD and % instructions) are set to OFF. This prevents differentiation
outputs from being output unexpectedly at the start of operation.
• An upwardly differentiated instruction (DIFU or @ instruction) will output
ON only when the execution condition is ON and flag for the previous
value is OFF.
Section 2-1
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