IBM EM78P447N Status of RST, T, and P of Status Register, Previous status before reset, Event

EM78P447N

8-Bit Microcontroller with OTP ROM

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

Product Specification (V1.1) 03.30.2005 • 21

(This specification is subject to change without further notice)