Learn shift registers without involving a microcontroller

shift-registers-without-a-microcontroller

This is a truly hands-on approach to learning. [Kevin Darrah] ditched the microcontroller and is using push buttons to learn about 595 shift registers. The test rig uses two of the serial-in, parallel-out chips. These are cascading which means that as data from the first chip overflows it feeds the input of the second. The parts are commonly used to drive LEDs, or reduce the number of pins needed to drive peripherals like this character LCD.

The five push-buttons give you a chance to intuitively learn how the chip logic works. The blank button is also commonly called Output Enable (OE). Driving it high shuts off the outputs of the chips but doesn’t clear the data. That task is performed by the clear button which is driven low to set all of the shift register memory to zero. The other three buttons set the logic level, shift it into the chip using the clock signal, and push the stored values to the outputs using the latch.

To get a visual approximation of what’s happening inside of these chips you should check out the shift register tutorial linked to in this post.

Comments

  1. zuul says:

    nice, be sure to check out his other vids too (kdarrah1234 on youtube)

  2. HC says:

    This isn’t how every digital circuits class teaches about shift registers?

    • saw0 says:

      I can not quite your comment

      • Dax says:

        Well, for example, the guy kinda glossed over the purpose of the “blank” signal, which is essential if you’re using shift registers to drive a data bus, because it puts the chip in a high-Z state where it doesn’t interfere with other registers in the same bus.

        That way you can connect many of these chips to the same output lines, and decide which one is allowed to talk by putting everyone else in blank.

  3. GenrusMajkertsc says:

    asf

  4. Ren says:

    I breadboarded something like this years ago (mid 90’s) too bad YouTube wasn’t around then to share it.

    • Bobby O says:

      Don’t rain on his parade. Almost everything on here has probably been done somewhere sometime before. This was posted for people new to HackADay that are interested in electronics but haven’t delved to deep, I am assuming. This was a good tutorial and he is good at explaining everything. I am glad it was posted and will be forwarding it to several of my friends that have been wanting to try and save me a lot of headache explaining shift registers to them.

  5. vonskippy says:

    Kids today and their fancy easy to understand training videos.

    In my day we learned from lengthy dry hard to comprehend text books – AND WE LIKED IT THAT WAY.

    Now get your Segway off my lawn.

  6. govind says:

    sir ur video is very good.but sir i want its circuit diagram send me plz

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