Suppose you pressed 'S4'. So the data transmitted will be 1110 and address will be of course 00000000.
HT12D receives the signals compares address thrice, gives high pulse on pin VT and then latch the data. Because data is 1110 LED L1 will not glow and rest all the LEDs will glow.
Same way if you press 'S2' data will be 1011. So now LED L3 will be off and rests are on.
But the result is same (All LEDs Lights-up except the pin where the Switch is connected (D0 to D3)).
But, Address/data (AD8-AD11) some times work and sometimes not.
I have tried connect LED to the data pin of encoder with 2N3904 Transistor and 10 K resistor. Same result. Also I have replaced old HT12E and HT12D with New pair. Same result. When I ground the TE Pin & AD8 of HT12E, the voltage on the pins of HT12E:
AD8 : -0.02
AD9 : 0.25
AD10: 0.25
AD11: 0.25
TE : 0.30
The receiver section is incredibly simple, but you need to remember that you can't drive just any load directly from the output pins of the HT-12D. Quite a few people have tried to directly connect relays, LEDs, solenoids, and just about everything else you could imagine to the data outputs directly, and found out the hard-way that it simply doesn't work.
The data output pins of the HT-12D decoder IC, D0 to D3 will source/sink only 1.6mA @5V. While not quite enough to drive an LED or relay, this is more than enough to drive a transistor or the ULN2803 high-current darlington transistor array.
Tip: One thing to remember about the HT-12D data outputs is that when the receiver circuit is first powered-up, the data output pins default logic state will be logic 0. When the HT-12D receives its first valid transmission each data output will then go to whatever logic state is on the encoder IC (HT-12A) data pins.
Have you solved the inverted logic (press button, LED goes out)?
Code C - [expand] 1 INTCON2bits.INTEDG1 = 1;
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