ETAS
Hardware Description
ETK-S20.1
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User Guide
24
4.11.2
ETK Trigger Generation
For generating triggers, the ECU software write index in the trigger register
"CBS_TRIG" by writing the index of the trigger in the trigger setting register
"CBS_TRIG".
The first 32 indexes of the trigger setting register "CBS_TRIGS" corresponds to
an index in the same position in the trigger register "CBS_TRIG", each of them
corresponding to an ETK hardware trigger.
The ETK periodically polls the trigger register "CBS_TRIG" via IO_READ_TRIG for
detecting triggers. The ETK sends a corresponding trigger message e.g. to the
ES590 which starts acquisition of appropriate measurement data. The polling
rate is determined by the fastest measurement raster and is configurable in a
10
µs to 50
ms range with a 50
µs default.
Active bits in trigger register "CBS_TRIG" are automatically cleared by CPU
when register is read by ETK via "IO_READ_TRIG".
4.12
Timer Triggering
The trigger mode "Timer Triggering" uses four internal timers of the ETK for
triggering. The trigger period of these timers is configurable by the user.
If trigger mode "Timer Triggering" is used handshake will be not executed. The
handshake is operated by an timeout defined in the A2L file.
The time intervals between trigger events are in accordance with the config
-
ured timer values. The periode of the time trigger has to be defined in the A2L
file. The maximum period duration is 1
second.
The timers works in an asynchronous manner to the ECU.
If variables are measured from ECC protected memories the ECU software
must ensure the proper initialization of these locations. A time-out period can
be set in the ETK configuration to allow for the ECU to initialize the memories
before the measurement begins.
NOTE
The selective setting of trigger bits is accomplished in hardware by the micro
-
controller and requires no Read-Modify-Write sequence by the ECU software.
NOTE
Only the index 0 to 31 corresponding to the first 32 triggers are supported by
ETK-S20.1.
