Interfacing ATMega32 to 74HC595 shift register

In digital or microprocessor system, shift register is use expand inputs outputs of the system. The 74HC595 is serial in parallel out shift register widely used for many years, due to its low cost and availability. It use three control lines:

1. serial clock line
2. serial data line
3. and latch output line

 

We just use these three line to make the output as many as we need. As and example of displaying a large size dot matrix display, or multi-digit seven segment display.

Some DIP package of SN74595 Shift Register IC

Pin diagram of 74HC959

For the operation the MSB of byte is shift into the register first, along with the Low-To-High clock transition. The latch pin is activate from low to high to output after the byte is completely shift out.

In this example, I use PORTC to interface with 74HC595 with seven segment display output. PD7 is used to count the input pulse and output to the register.

Schematic diagram of ATMega32 with 74HC595 shift register,
and single common cathode seven segments display.

I stored the code on gist.

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Back to main tutorial page ATMega32 tutorials in C with Atmel Studio 7.

See Also

1. ATMega32 SPI interfaces to 74HC165 and 74HC595 shift registers
2. Introduction to ATMega32 SPI Application With SN74HC595N
3. Interfacing the 74HC595 shift registers with PIC16F887 digital pins
4. PIC12F685 reading LM35 analog temperature sensor with 74HC595 driven seven-segment displays