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etc. Contact SHARP in order to obtain the latest device specification sheets before using any SHARP device.
SM3508
DESCRIPTION
The SM3508 is a CMOS 4-bit single-chip micro-
computer 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 spe-
cial 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 s
Operating temperature : 10 to + 60C
Supply voltage : 2.5 to 5.5 V
Package : 128-pin QFP (QFP128-P-2828)
[Test Sample only]
SM3508
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
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