- 1 -
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.
SM3518
DESCRIPTION
The SM3518 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 :
• 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]
SM3518
4-Bit Single-Chip Microcomputer
(For Data Bank Use)
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