XETK-S4.2 - User’s Guide
25
ETAS
Hardware Description
The XETK periodically polls the trigger register "CBS_TRIG" via IO_READ_TRIG
for detecting triggers. The polling rate is determined by the fastest measurement
raster and is configurable with a 50
μ
s default.
Active bits in trigger register "CBS_TRIG" are automatically cleared by the CPU
when the register is read by the XETK-S4.2 via IO_READ_TRIG.For generating
triggers, the ECU software sets bits in the trigger register "CBS_TRIG" by writing
the associated bits in the trigger setting register "CBS_TRIGS".
4.11
Timer Triggering
The trigger mode "Timer Triggering" uses four internal timers of the XETK-S4.2
for triggering. A fixed configurable period is used for triggering.
The time intervals between trigger events are in accordance with the configured
timer values. This values and their resolution have to be defined in the A2L file.
Available settings are:
• Minimum time interval 100
μ
s
• Maximum period duration 1 s
• Timer resolution 1
μ
s
The timers work in an asynchronous manner to the ECU.
4.12
Reset
The requirement for the XETK-S4.2 reset mechanism is to ensure that power-up
and power-down behavior of ECU is clean and smooth. The XETK-S4.2 normally
drives /PORST low during XETK power up or upon INCA request.
The signal /HDRST of the microcontroller is used by the XETK-S4.2 to detect
when the ECU is in reset.
The XETK-S4.2 senses the switched ECU power supply. This allows it to detect
when the ECU is off and forward this information to INCA. In addition, it allows
the XETK to enter the power save mode with the calibration system unplugged.
