7 segment display Pin outs?

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Kaellis991
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Re: 7 segment display Pin outs?

#41 Post by Kaellis991 »

I need to pay more attention to the avatars since I gloss over the names so easily.

Some good options to ponder between the path of least resistance and the learning experience.
Thanks to all for the help and to you Keith for the schematics...

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Keith Baxter
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Re: 7 segment display Pin outs?

#42 Post by Keith Baxter »

Joe,

On the boards that the AM code is based on display 1 is to the right and display 2 is to the left.

Display 2 dig1, dig2,dig3,dig4 Display 1 dig1,dig2,dig3,dig4
Then the 7219 is connected D7,D6,D5,D4,D3,D2 ,D1,D0

So as I said the way AM has written the code the string RIGHT ADDRESSES

Now on a a 6 digit display
Display 2 dig1, dig2,dig3, Display 1 dig1,dig2,dig3
Then the 7219 is connected D5,D4,D3,D2 ,D1,D0

I can assure you that the max works that way. I have many wired so.

Keith
AMD RYZEN 9 5950X CPU, Corsair H80I cooler, ASUS TUF GAMING B550-PLUS AMD Ryzen Mother Board,  32Gb ram Corsair Vengeance 3000Mh, MSI GTX960 4G graphics card 

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jph
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Re: 7 segment display Pin outs?

#43 Post by jph »

Keith Baxter wrote: Mon Dec 05, 2022 12:37 pm Joe,

On the boards that the AM code is based on display 1 is to the right and display 2 is to the left.

Display 2 dig1, dig2,dig3,dig4 Display 1 dig1,dig2,dig3,dig4
Then the 7219 is connected D7,D6,D5,D4,D3,D2 ,D1,D0

So as I said the way AM has written the code the string RIGHT ADDRESSES

Now on a a 6 digit display
Display 2 dig1, dig2,dig3, Display 1 dig1,dig2,dig3
Then the 7219 is connected D5,D4,D3,D2 ,D1,D0

I can assure you that the max works that way. I have many wired so.

Keith
Apologies, you are correct in respect of the wiring with regards D0 and D1 :D
Joe. CISSP, MSc.

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Keith Baxter
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Re: 7 segment display Pin outs?

#44 Post by Keith Baxter »

No worries Joe

We had this discussion some time ago. :lol:

Keith
AMD RYZEN 9 5950X CPU, Corsair H80I cooler, ASUS TUF GAMING B550-PLUS AMD Ryzen Mother Board,  32Gb ram Corsair Vengeance 3000Mh, MSI GTX960 4G graphics card 

Kaellis991
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Re: 7 segment display Pin outs?

#45 Post by Kaellis991 »

Keith Baxter wrote: Mon Dec 05, 2022 12:37 pm Joe,

On the boards that the AM code is based on display 1 is to the right and display 2 is to the left.

Display 2 dig1, dig2,dig3,dig4 Display 1 dig1,dig2,dig3,dig4
Then the 7219 is connected D7,D6,D5,D4,D3,D2 ,D1,D0

So as I said the way AM has written the code the string RIGHT ADDRESSES

Now on a a 6 digit display
Display 2 dig1, dig2,dig3, Display 1 dig1,dig2,dig3
Then the 7219 is connected D5,D4,D3,D2 ,D1,D0

I can assure you that the max works that way. I have many wired so.

Keith
Keith,

So if I replace the two 4 digit displays with the (2) 3-digit displays by means of some wiring, then this connection example will be the one to use?
E9EF65B7-C551-4CF3-9ECD-265A13E4181B.png

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jph
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Re: 7 segment display Pin outs?

#46 Post by jph »

Keith Baxter wrote: Mon Dec 05, 2022 12:46 pm No worries Joe

We had this discussion some time ago. :lol:

Keith
lol :D

Actually, in respect of the wiring I AM correct for the 8 digit, I just checked.
It is as I said before - from the left digit to the right digit the 7219 pins used are D7,D6, D5 D4 D3 D2 D1 D0

Also, what I said about using 6 digits is correct - IF USING YOUR OWN WIRING or making it yourself then you would just ignore pins D0 and D1 and wire the digits from left to right - for 6 digits, it would be as said (left to right digits - note digits - not 'blocks') 0,1,2,3,4,5 would be wired to D7,D6,D5,D4,D3,D2 respectively
If you then used the API as for an 8 digit module then "123456" sent to the 'new' unit would display exactly 123456.

I believe you are talking about some weird 6 digit board that someone found on the net that is wired in an illogical way. Is it that propwash thing ? - I don't believe that AM supports that board without code modification to rearrange the digits...
If you are making a board yourself, or a schematic to make a board, then why not simply ignore D0 and D1 which are the rightmost digits of the 8 and only use the first 6 ?

Is there some reason NOT to ?

Joe
Joe. CISSP, MSc.

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Keith Baxter
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Re: 7 segment display Pin outs?

#47 Post by Keith Baxter »

Kirk yes.


But you have to manipulate the string.

On a std 8 digit MAX7219 you would format so

Code: Select all

value = "  123.987"
string.format("% 9.03f",value)
To get the same display you would have to manipulate the string

Code: Select all

value = "123. 987 "
string.format("% 9.04f",value)




And Joe if you are using a 6 digit wired as I say

Code: Select all

value = "123.987"
string.format("% 7.03f",value)

Keith
AMD RYZEN 9 5950X CPU, Corsair H80I cooler, ASUS TUF GAMING B550-PLUS AMD Ryzen Mother Board,  32Gb ram Corsair Vengeance 3000Mh, MSI GTX960 4G graphics card 

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Keith Baxter
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Re: 7 segment display Pin outs?

#48 Post by Keith Baxter »

Joe,

Hook up a max and run the strings in the above post. You will see what is happening.


Keith
AMD RYZEN 9 5950X CPU, Corsair H80I cooler, ASUS TUF GAMING B550-PLUS AMD Ryzen Mother Board,  32Gb ram Corsair Vengeance 3000Mh, MSI GTX960 4G graphics card 

Kaellis991
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Re: 7 segment display Pin outs?

#49 Post by Kaellis991 »

@jph

Joe,
I have the same 7-segment display shown on the wiki page. Those are .56" tall digits.
My initial plan is to just replace those larger displays with the (2) 3-digit .3" displays I have.
Those 3 digit displays did not come with a board.

If that doesnt work, then I can use the larger 8 digits and create a bezel that will block out the left and right digits leaving only the middle 6 showing through my display window. Although I will still need to detach those two 4-digit displays so I can have them at 90 degrees to the too-long board. The board will need to be installed vertically while the digits will need to be horizontally mounted behind my bezel.

But this takes me back to my question about the decimal point...
Last edited by Kaellis991 on Mon Dec 05, 2022 1:36 pm, edited 1 time in total.

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jph
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Re: 7 segment display Pin outs?

#50 Post by jph »

I dont understand your issue Keith.

If I want to display 123.987 on the first 6 digits of an 8 digit max7219 module I would simply use
hw_chr_display_set_text(display_chr_id, "123.987")

Why would I be bothering with formatting :shock: ?

(and no, I DEFINITELY do not have any of the propwash 'things' :lol: )
Joe
Joe. CISSP, MSc.

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