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PT2249A_PT2250A V2.6

- 6 -

May, 2007

Remote Control Receiver IC

PT2249A_PT2250A

RECEIVING SIGNAL CHECK

The receiving signal check is used to check 2 cycle transmitting signals sent from the transmitter to

determine if it is a normal signal.

First, the data is stored in the 12-bit shift register. Then, when the second data is pushed into the shift

register, the data is forced out of the shift register by one bit where the first data has been stored. The

“pushed out” data and the incoming data are checked to see if they match. If there is an error in the

receiving signal of the 12-bit data check, the system is reset at that point. Conversely, when all

receiving data are checked OK, (HP1 ~ HP6 signals) outputs are raised from “L” level to “H” level.

CODE COMPARISON

To prevent interference with other models: C1, C2, and C3 code bits are provided to check whether the

transmitter and receiver codes match.

It is only when both codes match that the internal latch strobe pulse is generated to latch the receiving

data. The output is then raised from “L” level to “H” level. If both codes do not match, no latch strobe

pulse is generated and the output remains at “L” level (HPs and SPs) or unchanged (CPs).

The Code Bits used differ depending on the receiver. Please refer below.

Rx

PT2248 Code Pin

PT2249A

PT2250A

T1 (C1 Code)

Diode

C1

T2 (C2 Code)

C2

C2

T3 (C3 Code)

C3

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 will be set to “0”.