DESCRIPTION
The 3874 group is the 8-bit microcomputer based on the 740 family core technology. The 3874 group includes data link layer communication control circuit, A-D converters, D-A converter, automatic data transfer serial I/O, UART, and watchdog timer etc. The various microcomputers in the 3874 group include variations of internal memory size and packaging. For details, refer to the
section on part numbering. For details on availability of microcomputers in the 3874 group, re
fer to the section on group expansion.

FEATURES
● Basic machine-language instructions ...................................... 71
● Minimum instruction execution time................................. 0.32 µs
   (at 6.4 MHz oscillation frequency, in double-speed mode)
● Memory size
   ROM ............................................................... 16 K to 60 K bytes
   RAM ............................................................... 1024 to 2048 bytes
● Programmable input/output ports ............................................ 72
● Input port .................................................................................... 1
● Interrupts ................................................. 27 sources, 16 vectors
   (Interrupt source discrimination register exists, included key input interrupt)
● Timer 1, timer 2, timer 3 ................................................. 8-bit ✕ 3
● Timer X, timer Y............................................................ 16-bit ✕ 2
● Serial I/O1 .................... 8-bit ✕ 1(UART or Clock-synchronized)
● Serial I/O2 ................................... 8-bit ✕ 1(Clock-synchronized)
● Serial I/O3 ...................................................................... 8-bit ✕ 1
   (Clock-synchronized automatic data transfer/arbitrary bit transfer function available)
● A-D converter ................................................. 8-bit ✕ 8 channels
● D-A converter ................................................... 8-bit ✕ 1 channel
● Data link layer communication control circuit ............................ 1
● Clock generating circuit..................................... Built-in 2 circuits
   (connect to external ceramic resonator or quartz-crystal oscillator)
● Watchdog timer ............................................................ 20-bit ✕ 1
● Power source voltage ................................................ 3.0 to 5.5 V
● Power dissipation
   In double-speed mode ......................................................90 mW
   In high-speed mode ..........................................................60 mW
   (at 32 kHz oscillation frequency, at 5 V power source voltage)
   In low-speed mode .......................................................... 180 µW
   (at 32 kHz oscillation frequency, at 3 V power source voltage)
● Operating temperature range.................................... –40 to 85°C
   (Extended operating temperature version and automotive version)

APPLICATION
   Automotive comfort control for audio system, air conditioning etc., automotive body electronics control, household appliances, and other consumer applications, etc.