H8SX1663 datasheet(548/1158 Pages) RENESAS

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Section 9 I/O Ports

Rev.1.00 Jun. 07, 2006 Page 496 of 1102

REJ09B0294-0100

9.4

Usage Notes

9.4.1

Notes on Input Buffer Control Register (ICR) Setting

1. When the ICR setting is changed, the LSI may malfunction due to an edge occurred internally

according to the pin state. Before changing the ICR setting, fix the pin state high or disable the

input function corresponding to the pin by the on-chip peripheral module settings.

2. If an input is enabled by setting ICR while multiple input functions are assigned to the pin, the

pin state is reflected in all the inputs. Care must be taken for each module settings for unused

input functions.

3. When a pin is used as an output, data to be output from the pin will be latched as the pin state

if the input function corresponding to the pin is enabled. To use the pin as an output, disable

the input function for the pin by setting ICR.

9.4.2

Notes on Port Function Control Register (PFCR) Settings

1. Port function controller controls the I/O port.

Before enabling a port function, select the input/output destination.

2. When changing input pins, this LSI may malfunction due to the internal edge generated by the

pin level difference before and after the change.

• To change input pins, the following procedure must be performed.

A. Disable the input function by the corresponding on-chip peripheral module settings

B. Select another input pin by PFCR

C. Enable its input function by the corresponding on-chip peripheral module settings

3. If a pin function has both a select bit that modifies the input/output destination and an enable

bit that enables the pin function, first specify the input/output destination by the selection bit

and then enable the pin function by the enable bit.

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