ST6383 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
ST6383 Datasheet PDF : 82 Pages
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ST6380, ST6381, ST6382, ST6383, ST6388, ST6389
RESETS (Cont’d)
3.2.3 Watchdog Reset
The MCU provides a Watchdog timer function in
order to ensure graceful recovery from software
upsets. If the Watchdog register is not refreshed
before an end-of-count condition is reached, the
internal reset will be activated. This, amongst oth-
er things, resets the watchdog counter.
mode and enable interrupts. If no pending interrupt
is present at the end of the initialisation routine, the
MCU will continue by processing the instruction
immediately following the RETI instruction. If, how-
ever, a pending interrupt is present, it will be serv-
iced.
Figure 15. Reset and Interrupt Processing
The MCU restarts just as though the Reset had
been generated by the RESET pin, including the
built-in stabilisation delay period.
3.2.4 Application Note
No external resistor is required between VDD and
the Reset pin, thanks to the built-in pull-up device.
3.2.5 MCU Initialization Sequence
When a reset occurs the stack is reset, the PC is
loaded with the address of the Reset Vector (locat-
ed in program ROM starting at address 0FFEh). A
jump to the beginning of the user program must be
coded at this address. Following a Reset, the In-
terrupt flag is automatically set, so that the CPU is
in Non Maskable Interrupt mode; this prevents the
initialisation routine from being interrupted. The in-
itialisation routine should therefore be terminated
by a RETI instruction, in order to revert to normal
RESET
VECTOR
RESET
JP
JP:2 BYTES/4 CYCLES
INITIALIZATION
ROUTINE
RETI
RETI: 1 BYTE/2 CYCLES
VA00181
Figure 16. Reset Circuit
RESET
(ACTIVE LOW)
OSCILLATOR
SIGNAL
1k
VDD
300k
TO ST6
RESET
COUNTER
ST6
INTERNAL
RESET
WATCHDOG RESET
POWER ON/OFF RESET
VA0200E
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