CD74HCT164E

Logic - Shift Registers

The CD74HCT164E, produced by Texas Instruments, is an 8-bit serial-in/parallel-out shift register. This device processes data entered in the serial input (SI) on an asynchronous basis and utilizes an enable input (EI) to enable the data to be accepted. Register data can be accessed while data is being clocked into the register. The device typically operates at a low voltage of 2.0 V, allowing the device to use less power than conventional logic ICs.

The CD74HCT164E is commonly used as an address translator to provide two-way communication between devices. It can also be utilized to reduce the number of data lines used for data transmission. Additionally, it is suitable for multiplexing applications, including address, data, and control bits. Furthermore, the device is often used in digital timing circuits and devices requiring an asynchronous reset.

Working Principle

The main function of the shift register is to accept serial inputs and output them in parallel format. It consists of an array of flip-flops connected together in a shift register configuration. The serial data is input on the SI pin and shifted through the storage registers of the device upon receiving a clock pulse on the EI pin.

The data is transferred from one register to the next on each rising edge of the clock pulse. When the register is full, the last bit is stored in the output register and can be accessed at any time. The data can also be shifted out on the serial output (SO) pin, if required.

Cascading

The CD74HCT164E can be cascaded together in order to extend the length and number of data bits which can be processed. Two shift registers are connected together in a daisy chain configuration by connecting the SO pin of one register to the SI pin of the other register. This allows the serial data to be shifted into the first register, and then onto the second.

By cascading several registers together, more data can be processed and parallel data is available at the output register. It is also possible to cascade multiple registers together to create an 8-bit or 16-bit shift register. The registers must be connected in a daisy-chain configuration and all clock pulses must be synchronised.

Conclusion

The CD74HCT164E shift register is a versatile logic device which can be used for a variety of applications. It is a low power, fast access device, suitable for multiplexing, address translation, and digital timing circuits. The device can also be cascaded together, allowing for more data to be processed in a shorter amount of time.