ht12a encoder issue !!!! help asap
can ht12a can give 16 combinations or its only for 4 combinations
There are two similar circuits: HT12E and HT12A.
For the HT12E encoders, transmission is enabled by applying a low signal to the TE pin.
For the HT12A encoders, transmission is enabled by applying a low signal to one of the data pins D8~D11.
If a transmission enable signal is applied, the encoder scans and transmits the status of the 12 bits of address/ data serially in the order A0 to AD11 for the HT12E encoder and A0 to D11 for the HT12A encoder.
In a typical situation the HT12A transmitter IC works so that if pins 10...13 of IC are connected individually to the ground (this may create a maximum of 4 combinations) but they can be pulled to ground or what ever combinations of them by using some external diodes. This may upgrade the system up to a maximum of 16 combinations. See one example in the attached picture.
Pins 3...8 of HT12A are for setting the unique signal and important to set the same pins of receiver with identical settings. Otherwise the receiver will not decode the signal.
can u give little more info(working) of circuit