ETAS
Hardware Description
XETK-S21.0B
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User
Guide
21
4.6
ECU Voltage Supervisor
The ECU voltage (VDDP) is monitored by the XETK to recognize whether the
ECU is switched on or off. Additionally the ECU RAM standby voltage (VDDS
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BRAM) is monitored to determine if the standby RAM content is still valid.
These two signals are only used for monitoring therefore the load current is
negligible.
The XETK-S21.0 provides two opportunities to supply and supervise the ECU
RAM standby voltage:
A The XETK-S21.0 monitors the VDDSBRAM supply on board the XETK.
The microcontroller’s standby power supply pin must be connected to
the XETK pin VDDSBRAM.
B The XETK-S21.0 monitors the VDDSBRAMsense pin, provided by the
ECU connection. The microcontroller’s standby power supply pin must
be connected to the XETK pin VDDSBRAMsense. The microntroller’s
standby power supply may be provided by the ECU or by the XETK.
NOTE
The XETK-S21.0 only allows switching between reference page and working
page if there is a valid voltage at the sense pin and the working page has been
initialized by the calibration and development system.
