164 and 595 shift registers

[Stonent]

I just watched this video, I was aware of the 595 but not the 164 until I saw one for sale and googled the difference



The 595 is latched and he said that's why the LEDs don't flicker when transitioning, but he also said the 164 has a NAND gate on it. My thoughts were, what if you triggered a false on the NAND gate between transitions, could that eliminate the flickering?

Or if you connected VCC to a pin on the AVR and brought it high then sent your serial data and then brought it low to power down the 164?

Or would the flickering still happen because it's just something that happens during the data loading into the 164?

[mariush]

The 595 has the latch feature, but in this video he doesn't use it. As soon as he shifts the bits in, the leds light up, that's why you see the leds blinking ever so slightly as the active led moves around.

edit: nevermind, ignore what i said... i only watched a part of the video and I assumed the chip in the first part is 595 but it was actually the 164 one.

[Hideki]

You can certainly blank out all LEDs while shifting in new data, but it might still be visible as a slight flicker in the ones that should stay lit instead of a flicker in all of them.

Just use the 595 and make sure the outputs are latched before shifting in new data. After shifting in all 8 bits, let the new data through the latch and all LEDs will update at the same time.

[Stonent]

Well I figured I'd learn about both because I never know when I might encounter a 164. Now that I got to thinking about it I guess on a 164 I could put a transistor on the ground line running to the LEDs and flip it on after the bits have shifted and then flip it off afterwards.