ST7FLU05MCE View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST7FLU05MCE
STMicroelectronics
'ST7FLU05MCE' PDF : 124 Pages View PDF
ST7LUS5, ST7LU05, ST7LU09
On-chip peripherals
Note:
Software can use the timebase feature to set the WDGD bit at 1 or 2 ms intervals.
A watchdog reset can be forced at any time by setting the WDGRF bit. To generate a forced
watchdog reset, first watchdog has to be activated by setting the WDGE bit and then the
WDGRF bit has to be set.
The WDGRF bit also acts as a flag, indicating that the watchdog was the source of the reset.
It is automatically cleared after it has been read.
Caution: When the WDGRF bit is set, software must clear it, otherwise the next time the watchdog is
enabled (by hardware or software), the microcontroller will be immediately reset.
Hardware watchdog option
If hardware watchdog is selected by option byte, the watchdog is always active and the
WDGE bit in the LTCSR is not used.
t(s) Refer to the option byte description in Chapter 14: Device configuration and ordering
information.
uc Using halt mode with the watchdog (option)
rod If the watchdog reset on halt option is not selected by option byte, the halt mode can be
P t(s) used when the watchdog is enabled.
te c In this case, the HALT instruction stops the oscillator. When the oscillator is stopped, the lite
le u timer stops counting and is no longer able to generate a watchdog reset until the
d microcontroller receives an external interrupt or a reset.
so ro If an external interrupt is received, the WDG restarts counting after 64 CPU clocks. If a reset
b P is generated, the watchdog is disabled (reset state).
- O te If halt mode with watchdog is enabled by option byte (no watchdog reset on HALT
) le instruction), it is recommended before executing the HALT instruction to refresh the WDG
t(s o counter, to avoid an unexpected WDG reset immediately after waking up the microcontroller.
uc Obs Figure 30. Watchdog timing diagram
lete Product(s) - fWDG
so rod WDGD bit
tWDG
(2ms @ 8 MHz fOSC)
Hardware clears
WDGD bit
Ob te P Internal
watchdog
ObsoleRESET
Software sets
WDGD bit
Watchdog RESET
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