UJA1065 NXP Semiconductors, UJA1065 Datasheet - Page 13

• Manufacturer Part Number: UJA1065
• Manufacturer: NXP Semiconductors

Specifications of UJA1065

• Lead Free Status / RoHS Status: Supplier Unconfirmed

NXP Semiconductors
UJA1065_7
Product data sheet
6.4.1 Watchdog start-up behavior
6.4.2 Watchdog window behavior
The following corrupted watchdog accesses result in an immediate system reset:
Any microcontroller driven mode change is synchronized with a watchdog access by
reading the mode information and the watchdog period information from the same
register. This enables an easy software flow control with defined watchdog behavior when
switching between different software modules.
Following any reset event the watchdog is used to monitor the ECU start-up procedure. It
observes the behavior of the RSTN pin for any clamping condition or interrupted reset
wire. In case the watchdog is not properly served within t
and the monitoring procedure is restarted. In case the watchdog is again not properly
served, the system enters Fail-safe mode (see also
modes).
Whenever the SBC enters Normal mode, the Window mode of the watchdog is activated.
This ensures that the microcontroller operates within the required speed; a too fast as well
as a too slow operation will be detected. Watchdog triggering using the Window mode is
illustrated in
Fig 4.
•
•
Illegal watchdog period coding; only ten different codes are valid
Illegal operating mode coding; only six different codes are valid
trigger
via SPI
Watchdog triggering using Window mode
Figure
trigger point
last
4.
Rev. 07 — 25 February 2010
trigger
restarts
period
too early
(with different duration if
trigger restarts period
earliest possible
trigger point
period
High-speed CAN/LIN fail-safe system basis chip
50 %
desired)
trigger
via SPI
trigger window
Figure
too early
latest possible
trigger point
WD(init)
100 %
new period
possible
earliest
trigger
3, Start-up and Restart
50 %
point
, another reset is forced
window
trigger
possible
trigger
latest
100 %
point
UJA1065
© NXP B.V. 2010. All rights reserved.
mce626
13 of 76