DrLuke, a user at bildr, has written an in depth tutorial on the use of the 74HC595 8 bit shift register.
OK, so say you have this crazy cool idea where you need to control a ton of LEDs (I know, I know… LEDs). You looked at the multiplexer article, and that was great, but this idea is so cool, you need individual control of each LED, and turning them on one at a time just won’t do. Well again, we are here to help, and now it’s time to introduce you to the Shift Register. Not just any shift register, the super cheap, incredibly awesome 74HC595 8-bit Shift Register!
With a video, diagrams, even AVR and Arduino code samples!
We are angry, frustrated, and in pain because of the violence and murder of Black people by the police because of racism. We are in the fight AGAINST RACISM. George Floyd was murdered, his life stolen. The Adafruit teams have specific actions we’ve done, are doing, and will do together as a company and culture. We are asking the Adafruit community to get involved and share what you are doing. The Adafruit teams will not settle for a hash tag, a Tweet, or an icon change. We will work on real change, and that requires real action and real work together. That is what we will do each day, each month, each year – we will hold ourselves accountable and publish our collective efforts, partnerships, activism, donations, openly and publicly. Our blog and social media platforms will be utilized in actionable ways. Join us and the anti-racist efforts working to end police brutality, reform the criminal justice system, and dismantle the many other forms of systemic racism at work in this country, read more @ adafruit.com/blacklivesmatter
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !
Is there a reason he bit-bangs this instead of using the SPI peripheral?
I very much LOVE to see my article here!
Thank you very much 🙂
Likely because he is doing a demonstration on the 8 bit shift register, and not SPI peripheral…. Sometimes when you incorporate elegance into something you’re trying to effectively teach, it clouds the ultimate objective.
A very well-done tutorial! I wouldn’t mind seeing a matching tutorial for the ‘595’s “partner” – the 74HC165 (8-bit P>S shift register) for those who need byte-wide inputs.
Who could have guessed that something as apparently boring as an 8 bit shift register could become something of wonder.
One thing that may become an issue: according to my Philips datasheet, max ICC=+-75mA. As documented, the 180 ohm resistors to drive each LED will permit about 10mA (3V LED) to 15mA (2V LED) or so. If you drive all 8 at once, that’s 80mA to 120mA total current which is out-of-spec. Clearly this will work fine if you don’t drive all 8 LED’s, but that’s an unusual limitation.
At my tech college in the early 90’s we spent a lesson going through a heap of linear and digital ICs. We were shown a diagram of the internal circuitry on an overhead projector and hit with a few details from the datasheet.
Q. How and when would I use that?
A. We’ll get to that in the lab.
Two weeks later in the lab. “Don’t touch anything! These CRO’s are worth more than your life.”
So yeah I wish I had access to tutorials like this back in the 90’s. It doesn’t matter if there end up being hundreds of tutorials on shift registers. Someone will find this one and it will be the ‘one’ that makes sense to them.
Nice one, DrLuke. ! Keep up the good work, internet.
It’s really encouraging to see people liking my work 🙂
Hi, im trying to do a project using these shift registers, i looked this tutorial and its great, but i have a problem: in my project i use PIC16F887, and this code is for andruino o AVR. So i wonder if someone could help me to understand the code for PIC.