BU34381 Datasheet, PDF (9/10 Pages) Rohm – Single-chip 4-bit microcontroller for

Optical disc ICs
BU34381
FHardware descriptions
(1) Operates on a single power supply (VDD = 2.7 X
5.5V)
(2) Memory size
ROM
: 12288 8 bits
RAM
: 512 4 bits
LCD display RAM : 20 4 bits
(3) Instruction execution time (1 cycle instruction)
1.5µsec: (at 4MHz)
(4) Subroutine nesting : 8 levels
(5) Interrupts : 6 factors
External
: 3 factors
Internal (time counter, serial I / O) : 3 factors
(6) ROM data table function (data table area: 12KB)
(7) Two energy-saving modes (STOP / HALT)
(8) Internal 20-segment LCD driver adaptable for vari-
ous types of displays
Bias
:1/3
Duty settings : 1 / 3, 1 / 4 (programmable)
Internal bias resistor (3 stages, approx. 50kΩ)
(9) LCD segment output is program-switchable to
CMOS output
All 20 segments can be selected in 4-bit
groups
Resetting: CMOS small-current output port,
LOW polarity
(10) Internal remote control receiver (pulse width count-
er)
(11) Internal 8-channel, 8-bit A / D converter
(12) A / D input is programmable in 1-bit units as digital
input
(13) Internal 8-bit timer counter (also used as event
counter)
(14) Two internal serial input / outputs (LSB fast) that
simplify interface with external LSI chips
(15) 12 input / outputs (programmable pull-up)
(16) 5 inputs (programmable pull-up)
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