MAX7219 not responding?

Hardware Portenta Portenta Max Carrier
1

Hi, im trying to use a MAX7219 and some transistiors to drive large 4 inch 7 segment displays

However it seems that the MAX7219 is doing nothing i am connecting it as its on the schematics here, but for some reason the segment pins are constantly GND and the digits are constantly on, the segments are lighting always, the code is supposed to only turn on the A segment but it seems that the max7219 is not responding, any idea

The 7 segment displays are common anode and im using uln2803 to drive the currents

Is it normal for the segment pins to be all GND?

Please help

2

MAX7219 and ULN2803 ?
I wonder what's going on there.

3

You forgot to tell what display you're using.

4

I'm using 4 inch 7 segment display common anode

So in my mind the max7219 segment pin, let's say the pin corresponding to A, will be high when A segments need to be on

Because I'm using a common anode display I need to make then low by using the Darlingtons inside 2803

However all my segments outputs of my max7219 are GND, I check it with my multimeter

5

I'm thinking in putting out the Uln2803 and the nax7219 and just make the multiplexing using the Arduino pins directly and a BJT transistor for the digit pins

6

Now you forgot again.... this is a google search for 4 inch 7 display

You understand what I mean?

7

Yes I understand

I can't find the schematics of the display, but is this one

8

@momokash ,
I have deleted your other topic on the same subject, which you added to the end of another topic. Please do not add your questions on the end of other people's topics and please only start a topic once.

Please read the forum guide:

Thank you

1 Like
9

Well, that link leaves me just as clueless. But more important; we lack of a schematic or diagram over the circuit.

To enable us to help you, take some time to put together a schematic / diagram, ok?