Working of HT12E Encoder IC

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pin-diagram-configuration-IC-HT12E
Pin Diagram of IC HT12E

HT12E is a 2^12 series encoder IC widely used in remote control and very common among Radio Frequency RF applications. This HT12E IC capable of converting 12 bit Parallel data inputs into serial outputs. These bits are classified into 8 (A0-A7) address bits and 4(AD0-AD3) data bits. Using the address pins we can provide 8 bit security code for secured data transmission between the encoder and the decoder. The encoder and decoder should use the same address and data format. HT12E is capable of operating in a wide Voltage range from 2.4V to 12V and also consists of  a built in oscillator. Let’s move into the working of HT12E encoder IC.

PIN DESCRIPTION OF IC HT12E: 

The pin Description of the IC HT12E was pretty simple to understand with total of 18 pins.

  • VDD and VSS: Positive and negative power supply pins.
  • OSC1 and OSC2: Input and output pins of the internal oscillator present inside the IC.
  • TE: This pin is used for enabling the transmission, a low signal in this pin will enable the transmission of data bits.
  • A0 – A7: These are the input address pins used for secured transmission of this data. These pins can be connected to VSS for low signal or left open for high state.
  • AD0 – AD3: This pins are feeding data into the the IC. These pins may be connected to VSS for sending LOW since it is a active low pin
  • DOUT: The output of the encoder can be obtained through  this pin and can be connected to the RF transmitter.

WORKING OF HT12E IC: 

timing-diagram-ht12e-icHT12E starts working with a low signal on the TE pin. After receiving a low signal the HT12E starts the transmission of 4 data bits as shown in the timing diagram above. And the output cycle will repeats based on the status of the TE pin in the IC. If the TE pin retains the low signal the cycle repeats as long as the low signal in the TE pin exists. The encoder IC will be in standby mode if the TE pin is disabled and thus the status of this pin was necessary for encoding process. The address of these bits can be set through A0 – A7 and the same scheme should be used in decoders to  retrieve the signal bits.

PRACTICAL CIRCUIT USING HT12E:

HT12E-practical-application-circuit
Practical Application Circuit

The above diagram shows the practical set up of the HT12E encoder IC for better understanding on the working.

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Frank Donald

Junior Network Engineer at Tata Communications
Frank Donald is an Electronics and Communication Engineer who is very passionate about his subject. Reading, Surfing and Blogging are the things he loves.

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20 Comments on "Working of HT12E Encoder IC"

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NIKHIL SINGH
Guest

sir, from where can i get the whole kit of 433 mhz transmitter receiver.
please send me on nikhilsingh22895@gmail.com
I WANT THE WHOLE KIT WITH CONNECTION DIAGRAM AND ALL COMPONENTS.
I WILL BUY IT FOR ANY COST.
OR A READY MADE VERSION OF 433 MHZ RUNNING KIT WILL ALSO DO.

shailesh
Guest

What is the necessary of the OSC1 and OSC2 in the encoder and decoder fort transmission of the data

shailesh
Guest

What is the necessary of the OSC1 and OSC2 in the encoder and decoder fort transmission of the data

Guest

by default, if i do not give ground to data pins, then 1 is the output from the data output. That means this Ic provides some voltage which i found to be 0.24V by default at its data pins. And we are actually making the data input pins 0 by connecting them to ground using the switch. Am i right??

Rajesh
Guest

why we are use 434 Mhz frequency in patient monitoring system

Colin
Guest

Hi. If the address is different on the decoder then it can’t receive the data or ?

BISWAJIT
Guest

how to send 8bit data through this IC,do you have any idea?

narashiman parthasarathy
Guest

How to find Rosc for a specified baud rate or frequency ?

Frank Donald
Guest

Narashiman,
The HT12E uses a RC oscillator to generate the required frequency. Capacitor is built inside whose value is unknown, the external resistor we are going to use forms the RC oscillator. If you go through the datasheet you can find a graph ” Frequency vs Supply voltage” which gives the value of resistors to be used to generate required frequency. View the Graph in this link .Hope it helps, let me know if you need further clarification.

himanshu
Guest

How can I interface this if ht12e with 8051….pllzzzz….can u help me???

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