EM78P447N
8-Bit Microcontroller with OTP ROM
Product Specification
(V1.1) 03.30.2005
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21
(This specification is subject to change without further notice)
4.5.2 The Status of RST, T, and P of STATUS Register
A RESET condition is initiated by one of the following events:
1. A power-on condition,
2. A high-low-high pulse on /RESET pin, and
3. Watchdog timer time-out.
The values of T and P (listed in Table 8 below) are used to verify the event that
triggered the processor to wake up.
Table 8 shows the events that may affect the status of T and P.
Table 8 The Values of RST, T and P after RESET
Reset Type
T
P
Power on
1
1
/RESET during Operating mode
*
P
*
P
/RESET wake-up during SLEEP1 mode
1
0
/RESET wake-up during SLEEP2 mode
*
P
*
P
WDT during Operating mode
0
*
P
WDT wake-up during SLEEP1 mode
0
0
WDT wake-up during SLEEP2 mode
0
*
P
Wake-Up on pin change during SLEEP2 mode
*
P
*
P
*
P: Previous status before reset
Table 9 The Events that may Affect the T and P Status
Event
T
P
Power on
1
1
WDTC instruction
1
1
WDT time-out
0
*
P
SLEP instruction
1
0
Wake-Up on pin change during SLEEP2 mode
*
P
*
P
*
P: Previous value before reset
