H8SLASH3028F datasheet(673/923 Pages) RENESAS

部件名	H8/3028F

功能描述	Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

PDF	923 Pages

Scroll/Zoom	100%

制造商	RENESAS [Renesas Technology Corp]

网页	http://www.renesas.com

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673 / 923 page

Rev. 2.00, 09/03, page 643 of 890

20.4.4

Sample Application of Software Standby Mode

Figure 20.1 shows an example in which software standby mode is entered at the fall of NMI and

exited at the rise of NMI.

With the NMI edge select bit (NMIEG) cleared to 0 in SYSCR (selecting the falling edge), an

NMI interrupt occurs. Next the NMIEG bit is set to 1 (selecting the rising edge) and the SSBY bit

is set to 1; then the SLEEP instruction is executed to enter software standby mode.

Software standby mode is exited at the next rising edge of the NMI signal.

NMI

NMIEG

SSBY

NMI interrupt

handler

NMIEG = 1

SSBY = 1

Software standby

mode (power-

down state)

Oscillator

settling time

(tosc2)

SLEEP

instruction

NMI exception

handling

Clock

oscillator

Figure 20.1 NMI Timing for Software Standby Mode (Example)

20.4.5

Note

The I/O ports retain their existing states in software standby mode. If a port is in the high output

state, its output current is not reduced.

H8/3028F 数据表(PDF) 673 Page - Renesas Technology Corp