3 pin states during reset, Pin states during reset – FUJITSU Semiconductor Controller MB89950/950A User Manual

Page 62

Advertising
background image

48

CHAPTER 3 CPU

3.5.3

Pin States during Reset

Reset initializes the pin states.

Pin states during reset

When a reset source occurs, with a few exceptions, all I/O pins (peripheral pins) go to the high-impedance

state and the mode data is read from internal ROM (pins with a pull-up resistor (optional) go to the "H"

level).

Pin states after reading mode data

With a few exceptions, the I/O pins remain in the high-impedance state immediately after reading the mode

data (pins with a pull-up resistor (optional) go to the "H" level).

Note:

For devices connected to pins that change to high-impedance state when a reset source occurs take care

that malfunction does not occur due to the change in the pin states.

See Appendix E "MB89950/950A Series Pin States" for pin states at the time other than reset.

Advertising