Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
Programmable Encoder IC
PT2241
DESCRIPTION
PT2241 is a tri-state programmable encoder utilizing CMOS Technology specially designed for remote
control applications. It encodes address and data codes into a coded waveform suitable for RF
modulation and can provide up to 3
11
Address which may be designed by a one-time programmable
process. PT2241 can support up to 4 Data Bits, thereby reducing inventory pressures. It is housed in 8
or 16-pin DIP or SOP Package. The pin assignments and application circuit are optimized for easy
PCB Layout and cost saving advantage.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
CMOS technology
Low power consumption
Least external components
High noise immunity
Single resistor oscillator
Operating voltage: 1.8~15V
Up to 4 data pins
Up to 3
11
address codes
One-time programmable process
Available in SOP or DIP package
Reduction of inventory pressures
APPLICATIONS
•
•
•
•
•
Burglar alarm system
Car security system
Car/Garage door controller
Home/Office security system
Personal alarm system
PT2241 V1.5
-1-
March, 2006
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
Programmable Encoder IC
PT2241
BLOCK DIAGRAM
OSC
OSC
S yste m
Tim in g
V SS
V DD
PGM
Co n tr o l
Lo g i c
D0
D1
D2
D3
Da ta
Fu se D a ta /
A d dr e ss
Co d e
G e n er a ti o n
DO U T
S 0 S 1 V PG
PT2241 V1.5
-2-
March, 2006
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
Programmable Encoder IC
PT2241
PIN CONFIGURATION
8 PINS
VS S
VP G
PG M
N0/CO DE
1
2
3
4
P T 2 24 1 P
8
7
6
5
VDD
DOUT
O SC
D0 /CLK
16 PINS
VS S
S1
VP G
N3
D3
N2
D2
PG M
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
P T 2 24 1 P - 1 6
S0
VD D
DOUT
O SC
D0/CLK
N0/CO DE
D1
N1
PT2241 V1.5
-3-
March, 2006
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
Programmable Encoder IC
PT2241
PIN DESCRIPTION
Pin Name
VSS
S1, S0
-
I
I/O
Description
Negative power supply
Select pin
Normal=”High”
When these pins are set to “Low”, they are used to select
the number of data pins
Voltage program pin
Normal=”Floating”
When this pin is set to “Low”, the programmed “Low” bits
can be burnt-out
Data/Clock input pin
Normal=”Low” (Internal pull-low resistor)
When PGM=”High”, this pin functions as a Clock input
terminal
When the PGM=”Low”, this pin functions as a Data input
terminal
Data pins (Internal pull-low resistor)
These pins are determined by the state of S1 and S0
Normal=”Low” (Internal pull-low resistor)
When PGM=”High”, this pin functions as a Code input
terminal
Normally connected to D1~D3 (Internal pull-low resistor)
Program pin
Normal=”Low” (Internal pull-low resistor)
When this pin is set to “High”, PT2241 can be programmed
Oscillator pin
Data output pin
Normal=”Low”
When PGM is “High”, this pin shows the programming
status of PT2241
Positive power supply
Pin No.
8 pins 16 pins
1
1
-
16, 2
VPG
I
2
3
D0/CLK
I
5
12
D1, D2, D3
N0/CODE
N1, N2, N3
PGM
OSC
DOUT
VDD
I
I
I
I
I
O
-
-
4
-
3
6
7
8
10, 7, 5
11
9, 6, 4
8
13
14
15
PT2241 V1.5
-4-
March, 2006
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
Programmable Encoder IC
PT2241
FUNCTION DESCRIPTION
PT2241 encodes the address code (which are one-time programmable) and data into a special
waveform and outputs it to the DOUT. This waveform is fed to the RF modulator for transmission. The
transmitted radio frequency is received by the RF demodulator and reshaped into the special
waveform. PT2270 is then used to decode the waveform and set the corresponding output pin(s).
Thus, completing a remote control encoding and decoding function.
CODE BITS
A Code Bit is the basic component of the encoded waveform, and can be classified as either an
(Address/Data) Bit or a SYNC (Synchronous) Bit.
DATA BIT WAVEFORM
Data Bit can be designated as either Bit “0”, “1” or “f” if it is in “Low”, “High” or “Floating” State
respectively. One bit waveform consists of two pulse cycles and each pulse cycle has 128 oscillating
time periods. For further details, please refer to the diagram below:
α
OSC
B IT "0"
32
α
96
α
32
α
96
α
B IT "1"
96
α
32
α
96
α
32
α
B IT " f"
32
α
96
α
96
α
32
α
where: the oscillating time period,
α=1/f
and (f is the oscillation frequency)
As you can see in the diagram above, Bit “0” consists of 2 pulse cycles. Each Bit “0” pulse cycle goes
“High“ for 32α(where
α=
oscillating time period) then changes to “Low” for 96α. Likewise, Bit “1” has
2 pulse cycles and each Bit “1” pulse cycle consists of a “High” pulse for 96αis followed by “Low” Pulse
for 32α. For simplicity, let us designate one Bit “0” pulse cycle as a “Short Pulse” and one Bit “1” Pulse
Cycle as a “Long Pulse”. Then, we can say that a Bit “F” or a floating bit consists of a “Short Pulse”
followed by a “Long Pulse”.
PT2241 V1.5
-5-
March, 2006
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