H8S2245 datasheet(809/818 Pages) RENESAS

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Appendix E Pin States at Power-On

Rev.3.00 Mar. 26, 2007 Page 767 of 772

REJ09B0355-0300

Appendix E Pin States at Power-On

Note that pin states at power-on depend on the state of the

STBY pin and NMI pin. The case in

which pins settle* from an indeterminate state at power-on, and the case in which pins settle* from

the high-impedance state, are described below.

After reset release, power-on reset exception handling is started.

Note: *

"Settle" refers to the pin states in a power-on reset in each MCU operating mode.

E.1

When Pins Settle from an Indeterminate State at Power-On

When the NMI pin level changes from low to high after powering on, the chip goes to the power-

on reset state after a high level is detected at the NMI pin. While the chip detects a low level at the

NMI pin, the manual reset state is established. The pin states are indeterminate during this

interval. (Ports may output an internally determined value after powering on.)

The NMI setup time (t

NMIS) is necessary for the chip to detect a high level at the NMI pin.

VCC

STBY

NMI

RES

Power-on reset

tOSC1

NMI = Low

→ NMI = High

RES = Low

Manual reset

Figure E.1 When Pins Settle from an Indeterminate State at Power-On

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