ADVANCED AND EVER ADVANCING
MITSUBISHI ELECTRIC
MITSUBISHI 8-BIT SINGLE-CHIP MICROCOMPUTER
740 FAMILY / 38000 SERIES
38B5
Group
User’s Manual
MITSUBISHI
ELECTRIC
keep safety first in your circuit designs !
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products better and more reliable, but there is always the possibility that trouble
may occur with them. Trouble with semiconductors may lead to personal injury,
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of substitutive, auxiliary circuits, (ii) use of non-flammable material or (iii) prevention
against any malfunction or mishap.
Notes regarding these materials
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Preface
This user’s manual describes Mitsubishi’s CMOS 8-
bit microcomputers 38B5 Group.
After reading this manual, the user should have a
through knowledge of the functions and features of
the 38B5 Group, and should be able to fully utilize
the product. The manual starts with specifications
and ends with application examples.
For details of software, refer to the “740 Family
Software Manual.”
For details of development support tools, refer to the
“DEVELOPMENT SUPPORT TOOLS FOR
MICROCOMPUTERS” data book.
BEFORE USING THIS USER’S MANUAL
This user’s manual consists of the following three chapters. Refer to the chapter appropriate to your conditions,
such as hardware design or software development.
1. Organization
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CHAPTER 1 HARDWARE
This chapter describes features of the microcomputer and operation of each peripheral function.
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CHAPTER 2 APPLICATION
This chapter describes usage and application examples of peripheral functions, based mainly on
setting examples of relevant registers.
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CHAPTER 3 APPENDIX
This chapter includes a list of registers, and necessary information for systems development using
the microcomputer, the mask ROM confirmation (for mask ROM version), ROM programming confirmation,
and the mark specifications which are to be submitted when ordering.
2. Structure of Register
The figure of each register structure describes its functions, contents at reset, and attributes as follows:
(Note 2)
Bits
b7 b6 b5 b4 b3 b2 b1 b0
0
Bit attributes
(Note 1)
Contents immediately after reset release
CPU mode register (CPUM) [Address : 3B
16
]
b
0
1
2
3
4
5
6
7
Stack page selection bit
Name
Processor mode bits
b1 b0
Functions
0 0 : Single-chip mode
01:
Not available
10:
11:
0 : 0 page
1 : 1 page
At reset
R W
0
0
0
0
0
0
!
!
Nothing arranged for these bits. These are write disabled
bits. When these bits are read out, the contents are “0.”
Fix this bit to “0.”
Main clock division ratio selection
bits
0 0 :
φ
= X
IN
/2 (High-speed mode)
0 1 :
φ
= X
IN
/8 (Middle-speed mode)
1 0 :
φ
= X
IN
/8 (Middle-speed mode)
1 1 :
φ
= X
IN
(Double-speed mode)
b7 b6
1
0
: Bit in which nothing is arranged
: Bit that is not used for control of the corresponding function
Notes 1:
Contents immediately after reset release
0••••••“0” at reset release
1••••••“1” at reset release
Undefined••••••Undefined or reset release
T
••••••Contents determined by option at reset release
2:
Bit attributes••••••The attributes of control register bits are classified into 3 bytes : read-only, write-only
and read and write. In the figure, these attributes are represented as follows :
R••••••Read
••••••Read enabled
!••••••Read
disabled
W••••••Write
••••••Write enabled
!
••••••Write disabled
Table of contents
Table of contents
CHAPTER 1 HARDWARE
DESCRIPTION ................................................................................................................................ 1-2
FEATURES .................................................................................................................................... 1-2
APPLICATION ................................................................................................................................ 1-2
PIN CONFIGURATION .................................................................................................................. 1-2
FUNCTIONAL BLOCK .................................................................................................................. 1-3
PIN DESCRIPTION ........................................................................................................................ 1-4
PART NUMBERING ....................................................................................................................... 1-6
GROUP EXPANSION .................................................................................................................... 1-7
Memory Type ............................................................................................................................ 1-7
Memory Size ............................................................................................................................. 1-7
Package ..................................................................................................................................... 1-7
FUNCTIONAL DESCRIPTION ...................................................................................................... 1-8
Central Processing Unit (CPU) .............................................................................................. 1-8
Memory .................................................................................................................................... 1-12
I/O Ports .................................................................................................................................. 1-14
Interrupts ................................................................................................................................. 1-20
Timers ...................................................................................................................................... 1-23
Serial I/O ................................................................................................................................. 1-28
FLD Controller ........................................................................................................................ 1-40
A-D Converter ......................................................................................................................... 1-52
Pulse Width Modulation (PWM) ........................................................................................... 1-53
Interrupt Interval Determination Function ............................................................................ 1-56
Watchdog Timer ..................................................................................................................... 1-58
Buzzer Output Circucit .......................................................................................................... 1-59
Reset Circuit ........................................................................................................................... 1-60
Clock Generating Circuit ....................................................................................................... 1-62
NOTES ON PROGRAMMING ..................................................................................................... 1-65
NOTES ON USE .......................................................................................................................... 1-65
DATA REQUIRED FOR MASK ORDERS ................................................................................ 1-66
DATA REQUIRED FOR ROM WRITING ORDERS ................................................................. 1-66
ROM PROGRAMMING METHOD .............................................................................................. 1-66
MASK OPTION OF PULL-DOWN RESISTOR ......................................................................... 1-67
FUNCTIONAL DESCRIPTION SUPPLEMENT ......................................................................... 1-69
CHAPTER 2 APPLICATION
2.1 I/O port ..................................................................................................................................... 2-2
2.1.1 Memory assignment ....................................................................................................... 2-2
2.1.2 Relevant registers .......................................................................................................... 2-3
2.1.3 Terminate unused pins .................................................................................................. 2-6
2.1.4 Notes on use .................................................................................................................. 2-7
2.1.5 Termination of unused pins .......................................................................................... 2-8
2.2 Timer....................................................................................................................................... 2-10
2.2.1 Memory map ................................................................................................................. 2-10
2.2.2 Relevant registers ........................................................................................................ 2-11
38B5 Group User’s Manual
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