三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5021
ENCODER
GENERAL DESCRIPTION
The SM5021A/B is a h i g h p e r f o r m a n c e
infrared remote control encoder utilizing
CMOS technology. Mode A is a signal-key
control and mode B is a multi-key control
during data transmission, supports eight data
key inputs and a LED output to indicate the
status during transmission.
Auto power off function when key is not
pressed to save power, custom codes to
distinguish different products. SM5021
encoder is paired with SM5032 decoder for
more data control applications.
FEATURES
* Wide operation voltage range, 2.4V to 6V
* Eight data key control
* Option of signal-key or multi-key control
* Two custom codes to separate products
* Auto power off for saving power
* LED output to indicate transmission status
* Direct infrared LED 38KHz modulation output
* Low power consumption
* Paired with SM5032 decoder
* 16 pin DIP or SO package
APPLICATIONS
* SM3015 Fan Remote Control
* Audio Remote Control
* Toy Remote Control
* Consumer Products Remote Control
PIN ASSIGNMENT (TOP VIEW)
C1
C2
K1
K2
K3
K4
K5
Vss
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VDD
DOUT
LEDO
OSC2
OSC1
K8
K7
K6
SM5021A/B
Page 1
V.2.0 Mar 8,2002
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5021
ENCODER
FUNCTION DESCRIPTION
A. Encoder Singal Output Format
Bit Format
SYSCK / 192
Logic 1 is
Logic 0 is
EMPTY
Frame Format
There are four frames, encoder generates during sending. Each frame contains four field:
a) Frame head / Three-bits
1 1 0 ( Metal option )
b) Custom code / Two-bits
C1
C2
c) Control word / Seven-bits
0000001~1000110
d) Synch field / Four-bits of empty
B. Transmission Code Table
Start Word
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
Custom Code B1
C1
C1
C1
C1
C1
C1
C1
C1
C2
C2
C2
C2
C2
C2
C2
C2
0
0
0
0
0
0
1
1
B2
0
0
0
0
0
1
0
0
B3
0
0
0
0
1
0
0
0
B4
0
0
0
1
0
0
0
0
B5
0
0
1
0
0
0
0
1
B6
0
1
0
0
0
0
1
1
B7
1
0
0
0
0
0
1
0
Transmit
K1
K2
K3
K4
K5
K6
K7
K8
Page 3
V.2.0 Mar 8,2002
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5021
ENCODER
C. Transmission Timing
Key In
t1
OSC
LED
t2
DOUT
t3
Frame 1
Frame 2
Frame 3
Frame 4
t4
* t1: Key pressing > 32ms
* t2: Transmission time t3 + 108ms ( Four frame )
If t1 is over t3 + 108ms, DOUT will be transmitted again.
[ ( Pressing time ) MOD ( t3 + 108ms ) + 1 ] * 108ms + t3
* t3: Oscillator stable time.
OSC * 384 = 0.8ms
* t4: 3-Bits( Head ) + 2-Bits( Custom Code ) + 7-Bits( Data ) + 6-Bits( Empty ) = 18-Bits (27ms)
* OSC: 455KHz resonator
Page 4
V.2.0 Mar 8,2002
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