
HARDWARE
1-2
38B7 Group User’s Manual
DESCRIPTION/FEATURES
DESCRIPTION
The 38B7 group is the 8-bit microcomputer based on the 740 family
core technology.
The 38B7 group has six 8-bit timers, one 16-bit timer, a fluorescent
display automatic display circuit, 16-channel 10-bit A-D converter, a
serial I/O with automatic transfer function, which are available for
controlling musical instruments and household appliances.
FEATURES
<Microcomputer mode>
Basic machine-language instructions ....................................... 71
The minimum instruction execution time .......................... 0.48 s
(at 4.2 MHz oscillation frequency)
Memory size
ROM ........................................................ 60K bytes
RAM ....................................................... 2048 bytes
Programmable input/output ports ............................................. 75
High-breakdown-voltage output ports ...................................... 52
Software pull-up resistors . (Ports P64 to P67, P7, P80 to P83, P9,
PA, PB)
Interrupts .................................................. 22 sources, 16 vectors
Timers ........................................................... 8-bit 6, 16-bit 1
Serial I/O1 (Clock-synchronized) ................................... 8-bit 1
(max. 256-byte automatic transfer function)
Serial I/O2 (UART or Clock-synchronized) .................... 8-bit 1
Serial I/O3 (Clock-synchronized) ................................... 8-bit 1
PWM ............................................................................ 14-bit 1
8-bit 1 (also functions as timer 6)
A-D converter .............................................. 10-bit 16 channels
D-A converter ................................................................1 channel
Fluorescent display function ......................... Total 56 control pins
Interrupt interval determination function ..................................... 1
(Serviceable even in low-speed mode)
Watchdog timer ............................................................ 16-bit 1
Buzzer output ............................................................................. 1
Two clock generating circuits
Main clock (XIN–XOUT) .......................... Internal feedback resistor
Sub-clock (XCIN–XCOUT) .......... Without internal feedback resistor
(connect to external ceramic resonator or quartz-crystal oscillator)
Power source voltage
In high-speed mode ................................................... 4.0 to 5.5 V
(at 4.2 MHz oscillation frequency and high-speed selected)
In middle-speed mode ........................................... 2.7 to 5.5 V (*)
(at 4.2 MHz oscillation frequency and middle-speed selected)
In low-speed mode ................................................ 2.7 to 5.5 V (*)
(at 32 kHz oscillation frequency)
(*: 4.0 to 5.5 V for Flash memory version)
Power dissipation
In high-speed mode .......................................................... 35 mW
(at 4.2 MHz oscillation frequency)
In low-speed mode ............................................................. 60
W
(at 32 kHz oscillation frequency, at 3 V power source voltage)
Operating temperature range ................................... –20 to 85 °C
<Flash memory mode>
qSupply voltage ................................................. VCC = 5 V ± 10 %
qProgram/Erase voltage ............................... VPP = 11.7 to 12.6 V
qProgramming method ...................... Programming in unit of byte
qErasing method
Batch erasing ........................................ Parallel/Serial I/O mode
Block erasing .................................... CPU reprogramming mode
qProgram/Erase control by software command
qNumber of times for programming/erasing ............................ 100
qOperating temperature range (at programming/erasing)
..................................................................... Normal temperature
sNotes
1. The flash memory version cannot be used for application em-
bedded in the MCU card.
2. Power source voltage Vcc of the flash memory version is 4.0
to 5.5 V.
APPLICATION
Musical instruments, VCR, household appliances, etc.