Pc Operation; Asynchronous Operation - Omron SYSMAC CV Series Operation Manual

PC Operation

6-1-2 Asynchronous Operation

Program Execution
Basic processes
Cycle time and
memory check
Event processing
Write I/O memory
Write program
Read program
Monitoring
Forced Set/Reset
processing
Program execution
Refresh timers
Input and output refreshing
Interrupt processing:
I/O Interrupt program
Scheduled interrupt program
SYSMAC BUS refreshing
TIMH(015) refreshing (every 10 ms)
Scheduled refreshing
Timer refreshing (every 80 ms)
I/O bus check
Programming Precautions
Instruction Execution
The CV-series PCs can execute instructions and refresh I/O in parallel with
peripheral servicing (CPU Bus Units, Host Link Units, etc.). Peripheral servic-
ing will access data in the Link Area, SYSMAC BUS/2 Area, CPU Bus Unit
Area, and CPU Bus Link Area completely independently of program execu-
tion timing. This independent parallel processing is called asynchronous op-
eration.
Normally, instruction execution and peripheral servicing are independent,
however, an event processing request from a Unit is synchronized with pro-
gram execution. The cycle time for asynchronous operation is the time re-
quired for instruction execution.
Note *Only BASIC Units and Personal Computer Units are refreshed in CPU Bus Unit
servicing. Other CPU Bus Units are refreshed in interrupt processing.
When the PC is in asynchronous operation, instruction execution and peripheral
servicing accesses I/O memory independently.
Read
Write
Peripheral Servicing
Event
processing
request CPU Bus Unit servicing*
Unit #0 refreshing
Unit #0 event processing
Unit #15 refreshing
Unit #15 event processing
Peripheral Device servicing
Host interface servicing
Interrupt processing:
Write
PC Memory
Peripheral servicing
Read
Section 6-1
Basic processes
CPU bus check
Memory check
Battery check
Clock update
Start input check
SYSMAC NET Link refreshing
SYSMAC LINK refreshing
SYSMAC BUS/2 refreshing
CPU Bus Link refreshing
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