BU9729

Standard ICs Segment-type LCD driver BU9729K The BU9729K is a driver for segmented liquid crystal displays, which enables connection with a microcomputer through a serial interface. 4-bit common output and an internal power supply circuit for LCD drive make it possible to configure a low-cost display system. Applications Movie projectors, car audio equipment, telephones Features 1) Serial interface (8-bit length). 2) Display RAM: 72bits, internal (up to 72 segments can be displayed). 3) Internal power supply circuit for liquid crystal drive. 4) Display duty: 1 / 4. 5) Low-voltage and low-current operation supported. Block diagram VLCD VC LCD Driver Bias Circuit VDD VSS SEG1 SD SCK C/D CS Serial Interface Address Counter Display Data RAM (DD RAM) LCD Segment Driver 18bits SEG18 SEG2 Command / Data Register LCD Common Driver 4bits COM1 COM2 COM3 COM4 Command Decoder Timing Generator Common Counter OSC1 OSC2 1 Standard ICs BU9729K Pin assignments SEG10 SEG9 SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 17 16 SEG2 15 24 SEG11 25 23 22 21 20 19 18 SEG12 26 SEG1 SEG13 27 14 COM4 SEG14 28 13 COM3 SEG15 29 12 COM2 SEG16 30 11 COM1 SEG17 31 10 C/D SEG18 32 1 2 3 4 5 6 7 8 9 CS OSC1 OSC2 VLCD VDD VC SCK VSS Fig.1 2 SD Standard ICs BU9729K Pin descriptions Pin name OSC1 OSC2 VSS VC VLCD VDD SCK Pin No. 1 2 3 4 5 6 7 — I I/O I O — — Function These are the I / O pins for the internal oscillator. Resistance should be connected between t...