A-3-2 Cpu Unit Behavior - Omron CP1E - INTRODUCTION Introduction Manual

A-3 Inner Workings of CP1L/CP1E

A-3-2 CPU Unit Behavior

CPU Unit Operation Flow
A
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SYSMAC CP1L/CP1E Introduction Manual
This section briefly explains operations that take place within a CP1L or CP1E
CPU unit.
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
Overseeing
processes
Cycle
time
Program
execution
I/O refresh
*2
Peripheral
services
*1 CP1E CPU units do not execute these services.
*2 I/O refresh is performed in PROGRAM mode also.
· Initialize hardware memory and system work.
· Detect connected units.
· Execute automatic start-up transfer. *1
from memory cassette.
· Clear I/O memory.
· Check user memory (UM).
· Force-set/force-reset.
· Check for battery error.
· Monitor DIP switches. *1
· Check I/O bus.
· Check user program memory.
· 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)
Perform cyclic data exchange on the following units:
CP-series expansion I/O units
Services only executed on event occurrence:
· Peripheral USB port service
· Serial port service
· Communication port service *1
· Built-in flash memory/EEPROM access service
· Memory cassette access service *1
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