l99pm62gxp STMicroelectronics, l99pm62gxp Datasheet - Page 22

• Manufacturer Part Number: l99pm62gxp
• Description: Power Management Ic With Lin And High Speed Can
• Manufacturer: STMicroelectronics

Detailed description
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After power-on or standby mode, the watchdog is started with a long open window (65 ms
nominal). The long open window allows the micro controller to run its own setup and then to
trigger the watchdog via the SPI. The trigger is processed when the CSN input becomes
HIGH after the transmission of the SPI word.
Writing ‘1’ to the watchdog trigger bit terminates the long open window and start the window
watchdog (the timing is programmable by SPI). Subsequently, the micro controller has to
serve the watchdog by alternating the watchdog trigger bit within the safe trigger area (refer
to
After 8 watchdog failures in sequence, the V
subsequently, 7 additional watchdog failures occur, the V
and the device goes into V
In case of a watchdog failure, the outputs (RELx, OUTx, V
enters fail-safe mode (i.e. all control registers are set to default values except the ‘OUT3
control bit’).
The following diagrams illustrate the watchdog behavior of the L99PM62. The diagrams are
split into 3 parts. First diagram shows the functional behavior of the watchdog without any
error. The second diagram covers the behavior covering all the error conditions, which can
affect the watchdog behavior. Third diagram shows the transition in and out of Flash mode.
All 3 diagrams can be overlapped to get all the possible state transitions under all
circumstances. For a better readability, they were split in normal operating, operating with
errors and Flash mode.
Figure 9.
Figure
29). A correct watchdog trigger signal immediately starts the next cycle.
Watchdog in normal operating mode (no errors)
BAT
Doc ID 17639 Rev 3
standby mode until a wakeup occurs.
1
regulator is switched off for 200ms. If
1
2
regulator is completely turned off
) are switched off and the device
L99PM62GXP