SM3508 4-Bit Single-Chip Microcomputer (For Data Bank Use) SM3508 DESCRIPTION The SM3508 is a CMOS 4-bit single-chip microcomputer for databank incorporating data memory RAM, LCD driver (the output is adjustable in 16 steps for various contrast), key/switch input circuit, 8-bit parallel I/O port, 2 output ports and buzzer output circuit. The chip also has memory expansion controlling feature. One of two ports contains special output circuit for infrared (IR) communication. By connecting an external crystal, a 1 Hz timer is made possible for easier clock function. FEATURES • ROM capacity : Program ROM 12 k x 23 bits Character ROM 6 x 8 x 256 bits Constant ROM 1 k x 4 bits • RAM capacity : Working RAM 256 x 4 bits Display RAM 74 x 16 bits Data RAM 3 k x 8 bits • Memory expansion (external) : 1M x 8 bits x 3 • LCD display : 74-segment x 16-common • I/O ports : Parallel I/O 8 bits Input 2 bits Output 2 bits Buzzer output 1 bit (4 kHz) Key input 6 bits • Standby release : 2 events (2 Hz signal, key input) • Built-in oscillator : System clock (built-in CR oscillator) 1 MHz (external ceramic resonator) 1 MHz Timer (built-in CR oscillator) 32.8 kHz (external crystal) 32.768 kHz • Instruction cycle time : 3 µs • Operating temperature : –10 to + 60°C • Supply voltage : 2.5 to 5.5 V • Package : 128-pin QFP (QFP128-P-2828) [Test Sample only] In the absence of confirmation by device specification sheets, SHARP takes no responsibility for any defects that may occur in equipment using any SHARP devices shown in catalogs, data books, etc. Contact SHARP in order to obtain the latest device specification sheets before using any SHARP device. -1- SM3508 SYSTEM COMFIGURATION EXAMPLE (HIGH END DATA BANK) Common signal Segment signal CE S1-S74 CE1-CE3 H1-H16 S9-S28 Expand memory 1 M-byte x 3 V4 V3 V2 V1 VH RW SM3508 DIO1-DIO8 VCC EO2 Infrared signal for IR communication KI1-KI7 KI8 VCC TEST CCI CCO RESET CXI CXO BZ VCC VCC Key matrix S1-S8 S67-S74 (MAX. 112-key) + VCC SW 5V – RESET key Buzzer -2- SM3508 128 QFP (QFP128-P-2828) 0.38 0.15 ± 0.1 65 96 M 0.15 ± 0.05 (1.6) 0.8TYP. 64 128 33 28.0 ± 0.3 32 (1.6) (29.6) 31.2 ± 0.5 1.65 3.45 ± 0.2 31.2 ± 0.5 0.1 ± 0.1 Package base plane 1 (1.6) (1.6) 28.0 ± 0.3 0.15 97 -3-