
XETK-V1.0 - User’s Guide
31
ETAS
Hardware Description
4.12.2
External Watchdog disable
The XETK-V1.0 provides a method to disable an external watchdog circuit on the
ECU during braindead flashing.
The watchdog disable control signal in available on the VertiCal connector on
signal TOOL_IO0 (Pin L22). This signal is routed directly to a ball of the VertiCal
base board, completely bypassing the microcontroller on the VertiCal base
board.
When the XETK-V1.0 is configured to use this signal (Configuration parameter
"Use VertiCal TOOL_IO0 as Watchdog" set to "Yes"), the signal TOOL_IO0 is set
to logic high during brain dead flashing with the appropriate ProF command.
When "Use VertiCal TOOL_IO0 as Watchdog" is set to "No", the TOOL_IO0 pin
is not driven by the XETK-V1.0 (high-Z).
See chapter "Nexus (JTAG) Interface" on page 28 for details about the disable
watchdog logic circuit.
4.13
Reset
The requirement for ETK reset mechanism is to ensure that power-up and
power-down behavior of ECU is clean and smooth and to prevent corruption of
data stored in the ETK.
To accomplish this the XETK-V1.0 senses the VDDE2/3 of the ECU. This allows it
to detect when the ECU is off and forward this information to INCA. In addition,
it allows the ETK to enter the power save mode if the PC is off or unplugged.
Furthermore, the XETK-V1.0 senses the status of the /RESET and /RSTOUT lines
to generate a write protect signal for its memory.
Finally, the XETK-V1.0 generates a reset signal by pulling /RESET to keep the ECU
in reset while the ETK is in power save mode and to prevent the
μ
C from starting
until the ETK is ready to work.
The ETK is ready to work when it has has finished its initialization after leaving
power save mode or after initial power-up. This feature allows it also to reset the
ECU under tool control (required for INCA and ProF) and to perform an emer-
gency stop of the ECU in case of ETK failure.
The ETK is ready to work when it has has finished its initialization after leaving
power save mode or after initial power-up. This feature allows it also to reset the
ECU under tool control (required for INCA and ProF) and to perform an emer-
gency stop of the ECU in case of ETK failure.
Note
The first command of the downloaded flash driver must be a "NOP" command,
otherwise the driver will
not
work!