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URL: http://www.princeton.com.tw
Remote Control Decoder IC
PT2270
FUNCTION DESCRIPTION
PT2270 decodes the waveform received and fed into the DIN pin. The Waveform is decoded into code
word that contains the address, data and sync bits. The decoded address bits are compared with the
address set at the address input pins. If both addresses match for 2 consecutive code words, PT2270
drives -- (1) the data output pin(s) whose corresponding data bit(s) is then decoded to be a “1” bit, and
(2) the VT output -- to high voltage (high state).
CODE BITS
A Code Bit is the basic component of the encoded waveform, and can be classified as either an AD
(Address/Data) Bit or a SYNC (Synchronous) Bit.
ADDRESS/DATA (AD) BIT WAVEFORM
An AD Bit can be designated as Bit “0”, “1” or “f” if it is in low, high or floating state respectively. One bit
waveform consists of 2 pulse cycles. Each pulse cycle has 16 oscillating time periods. For further
details, please refer to the diagram below:
α
OSC
1 bi t = 32α
B IT 0
4α
B IT 1
12
α
B IT " f"
F l oati ng
4α
Where:
1.
α=Oscillating
Clock Period
2. Bit “f” is only available for address bits
SYNCHRONOUS (SYNC.) BIT WAVEFORM
1/8 b it w idth =4
α
4 bi t wi dth= 12 8α
Note: 1-bit=32α
PT2270 V1.3
-5-
May, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
