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FUJITSU MB91460 SERIES FR60 User Manual

Page 24

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8

Chapter 1 Introduction

4.How to Use This Document

Access size and address position

There are three kinds of accesses such as Byte access, Half-word access and Word access. However, note
that some registers have restricted access. For more information, see “3.2. I/O Map (Page No.24)” or “Detail
Description of Register” in each chapter.

B,H,W

: Byte access, Half-word access, and Wordaccess are allowed.

B

: Byte access (Be sure to access by Byte.)

H

: Half-word access (Be sure to access by Half-word.)

W

: Word access (Be sure to access by Word.)

B, H

: Byte access, Half-word access only (Word access is not allowed.)

H,W

: Half-word access, Word access only (Byte access is not allowed.)

Reference

The following describes address position to access.

• In Word access, address becomes multiple of 4. (Lowest order 2 bits mandatorily become “00”.)

• In Half-word access, address becomes multiple of 2. (Lowest order 1 bit mandatorily becomes “0”.)

• In Byte access, address will not be changed.

Therefore, for example, make RCR0 register to use Half-word access,

For address 0B0H, RCR1+RCR0 register is accessed.

(When address offset is +1 and +2, (Example: RCR0+UDCR1) Half-word access is not allowed.)

Offset

Register name

Write-only

Read-only

Byte access, Half-word access, and Word access are allowed.

Read/write

Initial value

Address offset value/Register name

Address

Up/down counter
0, 1

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