ETAS XETK-S22.0, Руководство пользователя

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ETAS Hardware Description
XETK-S22.0 - User’s Guide 28
4.12 Pinless Triggering
4.12.1 Startup Handshake
Microcontroller registers are used for XETK startup handshake. During this
handshake, ECU software detects the connected XETK by reading and writing
to specific registers and performing basic initializations based on the register
values. When these initializations are done, the handshake is finished with suc-
cess acknowledgment to the XETK. Thereafter, if a success acknowledgment
is received by the XETK, it starts additional initialization processes (e.g. cold-
start, checksum, downloads, etc).
Two different handshake mechanisms can be used by the XETK (one mecha-
nism uses DBG_STUP and DBG_TRG registers and the other one uses DBG_M-
BIN and DBG_MBOUT registers), please contact your local ETAS representative
for further information about the different handshakes.
Although different handshake mechanisms are supported by the XETK, ECU
software must ensure that all memory ECC initializations have been completed
prior to the startup handshake for any of them.
After the startup handshake and measure enabled, the XETK waits for triggers
from ECU software.
4.12.2 XETK Trigger Generation
To generate triggers, the ECU software sets bits by writing the associated trig-
ger index in the microcontroller trigger registers (DBG_TRGx). Each bit of the
trigger registers corresponds to an XETK hardware trigger.
The XETK periodically polls (reads) the trigger registers 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 registers are set.
Active bits in the trigger registers are automatically cleared by the microcontrol-
ler when the registers are read by the XETK.
NOTE
The selective setting of trigger bits is accomplished in hardware by the micro-
controller and does not require a Read-Modify-Write sequence by the ECU
software.