What is the HT12E Decoder?
The HT12E is a 12-bit serial encoder/decoder IC manufactured by Holtek Semiconductor. It is commonly used in wireless remote control systems to encode control signals sent from a transmitter and decode them in the receiver.
Some key features of the HT12E decoder:
- 12-bit data code
- Latching output
- Operating voltage: 2.4-12V DC
- Low power consumption
How Does the HT12E Decoder Work?
The HT12E contains a 12-bit shift register that is used to encode or decode data.
In encoding mode, the 12-bit parallel data is shifted out serially using the DATA pin when the TE trigger is pulsed. The encoded serial data contains address bits, data bits, and checksum bits.
|Number of Bits
In decoding mode, the serial data received on the DATA pin is shifted into the internal 12-bit register synchronized using the carrier pulses received on the DIN pin. The decoder compares the received address and checksum bits to check for errors. If no errors are detected, the data bits are transferred to the output pins.
The HT12E is commonly used in wireless remote control systems. A typical application circuit looks like this:
The encoder HT12E converts the parallel data into serial to transmit via the RF transmitter module. The decoder HT12E receives the encoded serial data, converts it back into parallel data and transfers it to the output pins to control a load.
Advantages of Using HT12E
Some of the benefits of using the HT12E decoder are:
- Simple integration into wireless systems
- Address recognition provides security
- Low power consumption suitable for battery powered devices
- High noise immunity with checksum feature
- Compatible with common RF transmitter/receiver modules
- Wide operating voltage range
Frequently Asked Questions
What is the power consumption of the HT12E?
The HT12E has very low power consumption, typically around 5mA in operating mode. This makes it suitable for battery-powered and wireless applications.
Does the HT12E require a quartz crystal?
No, the HT12E does not require an external quartz crystal. Its operation is controlled by the carrier pulses received from the RF receiver module.
What is the maximum transmission distance using HT12E?
The transmission distance depends on many factors like operating frequency, antenna design, environment etc. Typically you can achieve 20-30 meters indoor and 200-300 meters open-air line of sight transmission with a 315/434MHz RF module.
Can I cascade multiple HT12E to increase data bits?
Yes, multiple HT12E encoders and decoders can be cascaded to increase the number of data bits in the encoded data. For example, using 3 HT12E gives 36(12 x 3) bits for address, data, checksum.
What encoding scheme does HT12E use?
The HT12E uses its own proprietary encoding scheme. The encoded data contains address, data and checksum bits which allows the decoder IC to validate the received data.