BU34675 Datasheet | ROHM

Optical disc ICs Single-chip 4-bit microcontroller for CD-DA The BU34675 is a pact 4-bit, single-chip microcontroller that includes all the I / O required for CD system control. Circuits on the chip include a pulse width measurement counter (PWC), SIO, and an LCD controller / driver for a 28-segment display. The LCD segments can all be switched in software to CMOS output, and the extensive I / O allows many functions with a low pin count. FApplications Portable CD-DA, CD / radio / cassette players FFeatures 1) Low-voltage, high-speed operation (VDD = 2.3 to 5.5V at 4.4MHz). 2) Pulse width measurement counter on chip (for remote control reception). 3) SIO provided for munication with the DSP. 4) Seven-segment, four-mon LCD controller / driver on chip. 5) All segments of the LCD controller / driver output can be switched to CMOS output using software. FAbsolute maximum ratings (Ta = 25_C) FRemended operating conditions (Ta = 25_C) Optical disc ICs FBlock diagram Optical disc ICs FPin descriptions Optical disc ICs FInput / output circuits Optical disc ICs FElectrical characteristics (unless otherwise noted, Ta = 25_C and VDD = 5V) Optical disc ICs FElectrical characteristics (unless otherwise noted, Ta = 25_C and VDD = 3V) Optical disc ICs FExplanation of the hardware (1) Operates of a single power supply (VDD = 2.3 to 5.5V). (2) Memory size ROM: 6144 8 bits RAM: 256 4 bits LCD display RAM : 7 4 bits (3) Instruction time (one cycle instruction) 1.5µsec (at 4 MHz) (4) Sub-routine nesting: - - - . . 8 levels (5) Interrupts: 5 External - - - - - - . . 3 Internal (timer counter, serial I / O) - . . . . 2 (6) ROM data table function (6k data table region) (7) Two power save modes STOP / HALT (8) On-chip 7-segment LCD driver that can drive a wide variety of display types Bias - . . ....