Omron CP1L CPU - A-3-2 CPU Unit Behavior

A
A-3 Inner Workings of CP1L
SYSMAC CP1L Getting Started Guide 107
Appendix
A-3-2 CPU Unit Behavior
This section briefly explains operations that take place within a CP1L CPU unit.
 CPU Unit Operation Flow
Program executions (execution of instructions) are first processed, followed by I/O
refresh and execution of the peripheral servicing. These processes are repeated in
cyclic fashion.
Power ON
Power ON
(initialization)
processes
· Initialize hardware memory and system work.
· Detect connected units.
· Execute automatic start-up transfer
from memory cassette.
· Clear I/O memory.
· Check user memory (UM).
· Force-set/force-reset.
Overseeing
processes
· Check for battery error.
· Monitor DIP switches.
· Check I/O bus.
· Check user program memory.
Program
execution
· During execution: Execute user program.
· Error processing: Turn outputs OFF
(For bus errors, reset unit)
· When an error occurs: Clear I/O memory area
(except when executing FALS instructions)
I/O refresh
*
Perform cyclic data exchange on the following units:
CP-series expansion I/O units
Peripheral
services
Services only executed on event occurrence:
· Peripheral USB port service
· Serial port service
· Communication port service
· Built-in flash memory access service
· Memory cassette access service
*I/O refresh is performed in PROGRAM mode also.
· Online editing
Cycle
time
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