X20 system modules • Counter modules • X20DC4395
868
X20 system User's Manual 3.10
Timer
There are 8 timer events that the module can generate.
Information:
The timers have the highest event priority. All other system functions are interrupted when a timer
event occurs, and jitter for the amount of time it takes to process the event.
Idle event
Idle time is the time that remains after the system has processed all higher priority events and operations. The
module performs the following functions during idle time:
•
Handling of the asynchronous protocol
•
Mechanism for (re-)linking events
•
Operation of LEDs
•
Execution of event event functions linked to the idle function
4.11.17.12.5.2 Edge events
For each physical channel there are 3 event functions
•
Falling edge
•
Rising edge
•
Falling and rising edge
The respective event is triggered when an edge is detected on the hardware input and the "CfO_EdgeDetectRising"
and/or "CfO_EdgeDetectFalling" register has been configured for the respective channel.
Edges are detected by the hardware and processed for each interrupt. The interrupt handler uses an event distrib-
utor, which requires a specific amount of time for each edge to operate the hardware and execute linked event
functions. To reduce this time, edge detection can be enabled/disabled individually for each channel. To optimize
system load and I/O jitter, it is important to only enable edge detection where it is actually needed.
Information:
Edge detection can also be used for channels that are configured as outputs.
Event frequency limitation
To stabilize the system, there is a mechanism that limits the number of events created through edge recognition.
At least one idle event must occur between two edge events for the same edge.
The "CfO_FallingDisProtection" and "CfO_RisingDisProtection" registers can be used to disable this limitation for
each edge, and then an event will be generated for every edge. However, this can cause a system overload, i.e.
I/O operation can fail for up to 100 ms before the module changes to the reset state.
Generate event on falling edge
Name:
CfO_EdgeDetectFalling
This register defines whether an event is generated on a falling edge.
Data type
Value
USINT
See bit structure.
Bit structure:
Bit
Description
Value
Information
0
No event generated on falling edge.
0
Channel 1
1
Events 4096 and 4128 are generated on falling edge.
...
...
0
No event generated on falling edge.
7
Channel 8
1
Summary of Contents for X20 System
Page 2: ......
