ETAS
Hardware Description
BR_XETK-S3.0
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User Guide
26
4.9.2.2
XETK Trigger Generation
Initialization
After the startup handshake and measurement is enabled, the XETK is waiting
for triggers from the ECU software.
Application running
To generate triggers, the ECU software sets bits in the trigger register
"CBS_TRIG" by writing the associated bits in the trigger setting register
"CBS_TRIGS".
Each bit of the trigger setting register "CBS_TRIGS" corresponds to a bit in the
same position in the trigger register "CBS_TRIG", each of them corresponding
to an XETK hardware trigger.
The XETK periodically polls the trigger register "CBS_TRIG" via IO_READ_TRIG
for detecting triggers. The polling rate is determined by the fastest measure
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ment raster and is configurable with a 50 µs default.
Active bits in trigger register "CBS_TRIG" are automatically cleared by the CPU
when the register is read by the BR_XETK-S3.0 via IO_READ_TRIG.For generat
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ing triggers, the ECU software sets bits in the trigger register "CBS_TRIG" by
writing the associated bits in the trigger setting register "CBS_TRIGS".
4.9.3
Timer Triggering
The trigger mode "Timer Triggering" uses four internal timers of the BR_XETK-
S3.0 for triggering. A fixed 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 A2L
file. Available settings are:
• Minimum time interval 100
µs
• Maximum period duration 1
s
• Timer resolution 1
µs
The timers work in an asynchronous manner to the ECU.
4.9.4
Trace Triggering
The BR_XETK-S3.0 provides support for up to 64 trace triggers. The trace trig
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gers are defined within a section of RAM covered by a trace window. Both the
trace window and trace triggers are defined in the XETK’s configuration and/or
A2L file. A write by the microcontroller software to a trace trigger location
causes a trace trigger. The trace trigger events to the BR_XETK-S3.0 are syn
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chronous to the microcontroller software. Variables assigned to a measure
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ment raster using a trace trigger are acquired from the XETK’s trace mirror, not
directly via DAP. The BR_XETK-S3.0 supports value based data trace trigger up
to 255 value (up to 64 used in a single setup).
Requirements for trace triggering by the BR_XETK-S3.0:
• the triggers for different rasters/events have same address, but use dif
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ferent values
• the address must be 32 bit aligned
