The 38B4 group is the 8-bit microcomputer based on the 740 family core technology.

The 38B4 group has six 8-bit timers, a 16-bit timer, a fluorescent display automatic display circuit, 12-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

* Basic machine-language instructions ...... 71

* Minimum instruction execution time ........... 0.48 μs(at 4.2 MHz oscillation frequency)

* Memory size

ROM ............ 48K to 60K bytes

RAM .........1024 to 2048 bytes

* Programmable input/output ports ............ 51

* High-breakdown-voltage output ports ..... 36

* Software pull-up resistors (Ports P5, P61to P65, P7, P84to P87,P9)

* Interrupts ...... 21 sources, 16 vectors

* Timers ............... 8-bit ? 6, 16-bit ? 1

* Serial I/O1 (Clock-synchronized) ............. 8-bit ? 1z

(max. 256-byte automatic transfer function)

* Serial I/O2 (UART or Clock-synchronized) ......... 8-bit ? 1

* PWM .......... 14-bit ? 1, 8-bit ? 1 (also functions as timer 6)

* A-D converter ............. 10-bit ?12 channels

* Fluorescent display function ... Total 40 control pins

* Interrupt interval determination function .... 1

* Watchdog timer ..... 20-bit ?1