Hello,

i read this article:
https://forum.allaboutcircuits.com/threads/max7219-common-anode.95545/

The problem is that i already created the circuitry and i cannot control the segments, as i just swapped the segment and digit pins that i have read on another article but i now realized that it doesnt work due to the chips ahead.
So kgstewar from Post #11 recommended to just swap the ICs but then VCC and GND would be connected. So i wanted to ask:
Is there another way to control them?

2. I installed the libraries for the Raspberry Pi to control the MAX7219 with it. So if i changed the ICs would it actually work then? It's the spidev library for the MAX7219

Thanks for the replies and i hope for a quick reply to finish my project.

Sincerely, Cuby96

 

no one? i really want to finish my project

 

I think you will need to get the correct displays to use with the chip.

 

Well as the article i posted was made for common anode my question was if swapping the two chips is enough to make it work as the tread starter just told it but never told us if it actually worked or not

 

So no one gots an idea how to fix my problem?

 

Well as the article i posted was made for common anode my question was if swapping the two chips is enough to make it work as the tread starter just told it but never told us if it actually worked or not

It works. Reread my post #11 that you referenced in your first post. The first line is: "Quick follow up. The MAX7219 will indeed drive CA displays if you simply swap the UDN2981 and the ULN2803 shown in the circuit linked in my original post."

What I meant by that statement is that the MAX7219 will indeed drive CA displays if you simply swap the UDN2981 and the ULN2803 shown in the circuit linked in my original post.

 

So just switching and thats all? ok if its just that i can swap my circuit thanks alot

 

Ok new problem: i switched the two chips and wired them properly with 10V and ground as those chips are with the power supply obviously different connected. still the LED display can't be controlled via the raspberry pi itself. can somebody help me concerning this issue?

 

So i double checked again if every wire is at his place and still it doesnt work, maybe i need to use another library i use the one that is based on spidev which was from the raspberry simplified version to control the max7219. is there other libraries which i could use to check if some connections are somehow bad or is that the only one?

 

I don't know if this will be helpful at all but you seem to be a bit frustrated, so I am going to add my two cents.

I don't think you can easily use the 7219 with CA displays without attending to the software end. That is, if the driver is expecting you to use a CC (as I would expect), it may be necessary to deal with that eventuality.

Read this thread carefully. Even though it is for an Arduino driver, I am thinking that this is one problem that you may be having with the RP driver.

Hope it helps.

 

i see so its the RP software in the end? hmm depressing if i think that i build it for nothing, hmm thats sad, well.... i think i either have to use common cathode which will cost another 35€ in buying new ones ripping them out of the wooden case or i control them directly pin via pin through direct 10V control somehow