74HC595 connection problems

Hello,

I tried to work with the ShiftOut, did everything as it should be on the picture, but it seems that the 1uF doesnt work as planned.

Could it be because I should add a delay on the ShiftOut, or am I using the wrong capacitor? 100nF didnt seem to work either, except when I touched the 74HC595 with it.

You would have to provide some schematics here, or at least a link (sometimes I'm too lazy to google things like ShiftOut - sorry!).
Where exactly do you put this capacitor? It (most likely) should be across the power, from plus Vcc to GND, for decoupling noise.

Could it be because I should add a delay on the ShiftOut, or am I using the wrong capacitor?

Unlikely, both.

e100nF didnt seem to work either, except when I touched the 74HC595 with it.

Where? And what worked when?

I got the following:

  1. No capacitor
    Everything working fine, except that it got noise (instead of giving all leds when i put 255 in, it randomly makes most leds visible or gives noise)

  2. 100nF when booting/resetting
    No leds show up, or the last visible leds show up.

  3. 100nF touching
    Every led goes to his correct state.

I touch the latchPin(12) with the capacitor, and that one is connected to ground (8).

I still would like a description of how you have connected the '595. Have you connected to "not-OE" (output enable, pin 13) to GND? If not it could be floating (for example).

When you reset the '595 only the shiftregisters are (or should be) affected, not the output storage registers (until you load them with a pulse on the ST input - (storage trigger?) - pin 12).

I really don't understand how your point #3 can work, unless you are not using this input, and it is floating, until you ground it via the capacitor, perhaps.

There are two different clocks in use with the '595, one for shifting the data into the shiftregisters (The SH input, pin 11), which is not the output, and another one (the aforementioned ST input), which puts the contents of the internal shiftregister on the output pins (the storage registers).

This is how its connected.

When I do option 3, I just put the 100nF between 12 (latch) and 8 (GND).

When I do option 3, I just put the 100nF between 12 (latch) and 8 (GND).

Do not do this, it is a rogue tutorial and it can damage your arduino if you place a capacitor directly on an output pin.
Put a 0.1uF across each shift registers supplu pins as close to the chip as possible. Make sure your ground connections are correct and solid.

So, 100nF between VCC (Pin 16) and GND (Pin 8)?

Yes on every shift register, and other chips if you have them.
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

Okay... That explains a lot.

Thanks for the extra info. Even though I am still student at an ICT-Electronics department, it seems they never thought about telling us about these kind of problems. :-[

Yes I know, I used to tell my students but I only got them in their final year, no one had told them before. That's why I made the page and am always banging on about it. It is the cure of over 80% intermittent operations on this forum.