H8SLASH3028F datasheet(69/923 Pages) RENESAS

Part #	H8/3028F

Description	Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

PDF	923 Pages

Scroll/Zoom	100%

Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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69 / 923 page

Rev. 2.00, 09/03, page 39 of 890

2.6.5

Notes on Use of Bit Manipulation Instructions

The BSET, BCLR, BNOT, BST, and BIST instructions read a byte of data, modify a bit in the

byte, then write the byte back. Care is required when these instructions are used to access registers

with write-only bits, or to access ports.

Step

Description

Read

Read one data byte at the specified address

Modify

Modify one bit in the data byte

Write

Write the modified data byte back to the specified address

Example 1: BCLR is executed to clear bit 0 in the port 4 data direction register (P4DDR) under

the following conditions.

P47, P46:

Input pins

P45 – P40: Output pins

The intended purpose of this BCLR instruction is to switch P40 from output to input.

Before Execution of BCLR Instruction

P47

P46

P45

P44

P43

P42

P41

P40

Input/output

Input

Output

DDR

0011

1111

H8/3028F Datasheet(PDF) 69 Page - Renesas Technology Corp