going out on a limb and praying the schematic is correct

[MrDEB]

my Christmas 2025 project I had to redo (see posthttps://www.electro-tech-online.com/threads/using-a-rtc-in-sf-basic.166376/post-1460947
and have yet to get a 74hc595 to work properly but it should work as per schematic.
Am aware this is asking for more problems but hopefully not.

 

[Ian Rogers]

I know I'm always late at these parties, but there is a serial chip that you may find a lot easier.
It has 32 segments and current control. Its a MAX 7219 and they can be connected as one.
So you will have 96 LEDs' with just three devices.

Just a thought.

 

[MrDEB]

Looked at the data sheet. Looks promising.
THANKS

 

[MrDEB]

I recall I went down this road and sevral members suggested the 74hc595 would be a better choice.
After looking over data sheet etc. I have to agree that the 74hc595 is a better choice.

 

[tumbleweed]

Don't ground the QH' outputs

As to the rest of it, whatever floats your boat. Why you have some CLK pins common and others not I don’t follow... you will have to deal with them differently

 

[MrDEB]

The reason I grounded the OH outputs is I was doing some research into issues with using the 74hc595.
The article suggested grounding or taking unused pins high.
I need to review my schematic for misconnections etc.
IF I get to the point of having boards made will be happy to share. My plan is to have JLPBC assemble the front (all the LEDs)
Thanks for your guidance

 

[MrDEB]

I checked the CLK pins and they are all connected?
oups found one after I highlighted the net
thanks

 

[tumbleweed]

Do not leave unused INPUTS floating/unconnected.
Unused outputs can be left unconnected.

You have two of the HC595 using separate CLK6 and CLK8 signals, while the rest all use CLK1.
I don't know if that's intended or not

 

[MrDEB]

I corrected them
Will remove the ground from the OH pins

 

[tumbleweed]

You may want to think really long and hard about how you have the 595s connected and what that does to the code.

There are a number of different options, each with different advantages and disadvantages.

I'm not sure what you're looking to accomplish with the 595s vs all your other led projects

 

[be80be]

https://g.co/gemini/share/00204c305957 Try it out
You could twinkle all you want

 

[be80be]

Here the link to where the AI tells all about using 74HC595

Gemini - 74HC595 Chaining and Bit Shifting

Created with Gemini

g.co