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Remote Control Decoder
PT2272
VALID TRANSMISSION
When PT2272 receives a transmission code word, it initially checks whether this is a valid transmission.
For a transmission to be valid, (1) it must be a Complete Code Word, and (2) the Address Bits must
match the Address Setting at the Address Pins. After two consecutive valid transmissions, PT2272 (1)
drives the data pins according to the data bits received, and (2) raises VT to high voltage (high state).
The timings are shown in the following diagram.
Sync bit
Sync bit
1st word 2nd word
DIN
t
a
tc
Data pins
(momentary)
t
b
VT
ta = 8 OSC clock width
tb = 1 OSC clock width
tc = 2 code word width
LATCH OR MOMENTARY DATA OUTPUT TYPE
PT2272 uses either the latch or the momentary data output type depending on the PT2272 version
used. The latch type (PT2272-Lx) activates the data out during transmission and this data is sustained
in the memory until another data is inputted or entered. A momentary type (PT2272-Mx), on the other
hand, activates the data out only during transmission. In the momentary type, the data does not remain
in the memory after the transmission is completed. Please refer to the diagram below:
DATA WORDS
DATA WORDS
DIN
T
T
DATA PINS
(Momentary)
DATA OUTPUT X
DATA OUTPUT Y
DATA PINS
(Latch)
DATA OUTPUT X
DATA OUTPUT Y
VT
T = 2 CODE WORDSWIDTH
PT2272 V3.7
- 10 -
June, 2008
PTC [ PRINCETON TECHNOLOGY CORP ]
