ETAS
Hardware Description
XETK-S31.0
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User
Guide
22
4.9.2
XETK Trigger Generation
To generate triggers, the ECU software sets bits by writing the associated trig
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ger index in the "DTS_SEMAPHORE" register.
Each bit of the "DTS_SEMAPHORE" corresponds to an XETK hardware trigger.
Within the XETK’s configuration and/or A2L file, bit 0 corresponds to hardware
trigger 1 and bit 31 corresponds to hardware trigger 32.
The XETK periodically polls (reads) "DTS_SEMAPHORE" via JTAG. The polling
rate is configurable, with 50 µs default. The XETK then starts acquisition of
appropriate measurement data based on which bits of the register are set.
Active bits in "DTS_SEMAPHORE" are automatically cleared by the microcon
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troller when the register is read by XETK.
4.10
Timer Triggering
The trigger mode "Timer Triggering" uses four internal timers of the XETK-
S31.0 for triggering. A configurable period is used for triggering.
The time intervals between trigger events are in accordance with the config
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ured timer values. This values and their resolution have to be defined in the
XETK’s configuration and/or A2L file. Available settings are:
• Minimum time interval 100
µs
• Maximum period duration 1
s
• Timer resolution 1
µs
The timers trigger the XETK in an asynchronous manner to the microcontroller
software. Variables assigned to a measurement raster using a timer trigger are
acquired from their original locations in RAM via JTAG.
NOTE
The selective setting of trigger bits is accomplished in hardware by the micro
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controller and does not require a Read-Modify-Write sequence by the ECU
software.
NOTE
Only the index 0 to 31 corresponding to the first 32 triggers are supported by
the XETK-S31.0
NOTE
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 XETK configuration to allow for the ECU to initialize the memo
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ries before the measurement begins.
