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Infrared Remote Control Transmitter
PT2248
The PT2248 Code Bits Connection Table for PT 2249A / PT 2250A Series Application is given below:
Rx
PT2248 Code Pin
T1 (C1 Code)
T2 (C2 Code)
T3 (C3 Code)
PT2249A
Diode
C2
C3
PT2250A
C1
C2
Diode
Note: where C1, C2, C3 will be “1” if one diode is connected between CODE and Tn pins; n=1 to 3 in
PT2248; otherwise, it will be set to “0”.
Note: When communicating with any of the PT2249A Series Receivers, C1 Code Bit Data is not used.
Therefore, it is necessary to connect diodes to the Code terminal corresponding to C1 Code Bit
of PT2248. (In this way, the C1 Code Bit of PT2248 transmits “1”. Likewise, when
communicating with any of the PT2250A Series Receivers, C3 Code Bit is not used. Therefore,
it is necessary to connect diodes to the Code Terminal corresponding to the C3 Code Bit of
PT2248.)
TRANSMITTING WAVEFORM
a
3a
Co de Bi t
Con tinu ous /
S ingl e- Sh ot Code
48 a
K ey Inp ut Cod e
The diagram above shows the basic transmitting waveform. A basic transmitting waveform consists of
12-bits serial data.
The time of bit “a” is dependent on the oscillation frequency (fosc) and is given by the following formula:
a=
1
x 192
fosc
PT2248 V2.7
-7-
June, 2005
PTC [ PRINCETON TECHNOLOGY CORP ]
