TLE8262-2E Datasheet, PDF (55/94 Pages) Infineon Technologies AG – Universal System Basis Chip

TLE8262-2E
Supervision Functions
11.1.4 Reset from Outside
If the reset pin RO is pulled to low from outside while no reset low is issued by the SBC, the device goes to Restart
Mode. In Restart Mode an reset is issued by the SBC, the RO pin is set to low for the time t_RD1 or t_RD2. If the RO
pin is pulled to low for longer time Reset clamped is detected.
11.2
Watchdog
Two different Watchdogs are possible in the SBC. It can be either a Window Watchdog or a Time-out Watchdog.
The Watchdog can also be inhibited in SBC Stop Mode and SBC SW Flash Mode via SPI. The Watchdog timing
is programmed via SPI command. As soon as the Watchdog is activated, the timer starts running and the
Watchdog must be served. Please refer to Table 10 to match the SBC Modes with the Watchdog Modes.
The default setting for the Watchdog is Time-out Watchdog with a 256 ms timer. The long open window allows the
microcontroller to run its initialization sequences and then to trigger the Watchdog via the SPI.
The Watchdog is served by a SPI bit and should toggle with the correct frequency. The default value is a 0, so the
first trigger bit must be a 1.
In case of a Watchdog reset, the Watchdog immediately starts with a long open window when entering SBC
Normal Mode. With the reset the watchdog bit is set to 0, so the first watchdog trigger after reset is a change to 1.
In SBC Software Development Mode, no reset is generated due to watchdog failure, if a watchdog failure occurs
it is indicated by the SPI Reset bit and via INT pin. All watchdog modes are accessible in regards to the normal
operation modes.
Table 10 Watchdog Functionality by SBC Modes
SBC Mode
Watchdog Mode
Remarks
INIT Mode
Watchdog Programmable;
Watchdog is not active.
INIT Mode should be left in less than 256 ms (see
Chapter 13)
Normal Mode
WD Programmable;
–
Time-out or Window Watchdog
Software Flash Mode Mode is fixed
SBC retains the set-up as in the mode before entering
the Software Flash Mode
Stop Mode
Mode is fixed
SBC retains the set up as in the mode before entering
the Stop Mode
Sleep Mode
OFF
SBC does not retain the set-up.
Fail-Safe Mode
OFF
SBC does not retain the set-up
Restart Mode
OFF
SBC will start default Watchdog setting (256ms
Time-out Watchdog) when entering Normal Mode.
Data Sheet
55
Rev. 1.0, 2009-05-26