B4R Question Does anyone have the library for MAX7219cng led dotmatrix ?

[vali khandangoll]

Hi all of you.
I have a Led dotmatrix display with MAX7219cng IC like below.
I tried many libraries but none worked.

If anyone has a library for it with a small sample code please send it.

 

[candide]

this one ? https://www.b4x.com/android/forum/threads/rmax7219ledmatrix.69861/#content

 

[janderkan]

And the forum search is always a good place to start: https://www.b4x.com/android/forum/pages/results/?query=max7219

 

[vali khandangoll]

this one ? https://www.b4x.com/android/forum/threads/rmax7219ledmatrix.69861/#content

hi again
I saw your examples and used that.

your code show error like picture below.

I can use setcolumn currectlly like picture below but can not use setchar.
I want to show a character in dotmatrix display only.

 

[emexes]

I want to show a character in dotmatrix display only.

Did you get this going?

I suspect the easiest way to display that character is to send the 8-by-8 bitmap directly as 8 x 8-bit bytes, eg:

00100100 = 32 + 4 = 36
01011010 = 64 + 16 + 8 + 2 = 90
10000001 = 128 + 1 = 129
10000001 = 128 + 1 = 129
10000001 = 128 + 1 = 129
01000010 = 64 + 2 = 66
00100100 = 32 + 4 = 36
00011000 = 16 + 8 = 24

which will end up looking like:

SetDigitSegments(0, 36)
SetDigitSegments(1, 90)
SetDigitSegments(2, 129)
SetDigitSegments(3, 129)
SetDigitSegments(4, 129)
SetDigitSegments(5, 66)
SetDigitSegments(6, 36)
SetDigitSegments(7, 24)

The chip numbers digits 1-to-8 rather than the more-usual 0-to-7. The library might "fix" this for you.

You could write an intermediate Sub that loads up those 8 digits in one call eg:

SetAllDigitsSegments(36, 90, 129, 129, 129, 66, 36, 24) 'display heart symbol

Once you've got a character displaying using "manual" code then, depending on how many different characters you plan to display, you can either code up the rest of them manually as well, or put some effort into working out how to use the library's character generator code.

edit: Your display might be wired up with bytes as columns rather than as rows. If it is wired up as columns, then your heart will be rotated 90 degrees. One solution is to physically rotate the display 90 degrees so that your heart is upright. Or you could change the wiring. Or you could recalculate those byte values, but: your life will be much easier if the display is arranged in the same format as binary numbers, per the example above.

https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf

 

[vali khandangoll]

Did you get this going?

I suspect the easiest way to display that character is to send the 8-by-8 bitmap directly as 8 x 8-bit bytes, eg:

00100100 = 32 + 4 = 36
01011010 = 64 + 16 + 8 + 2 = 90
10000001 = 128 + 1 = 129
10000001 = 128 + 1 = 129
10000001 = 128 + 1 = 129
01000010 = 64 + 2 = 66
00100100 = 32 + 4 = 36
00011000 = 16 + 8 = 24

which will end up looking like:

SetDigitSegments(0, 36)
SetDigitSegments(1, 90)
SetDigitSegments(2, 129)
SetDigitSegments(3, 129)
SetDigitSegments(4, 129)
SetDigitSegments(5, 66)
SetDigitSegments(6, 36)
SetDigitSegments(7, 24)

The chip numbers digits 1-to-8 rather than the more-usual 0-to-7. The library might "fix" this for you.

You could write an intermediate Sub that loads up those 8 digits in one call eg:

SetAllDigitsSegments(36, 90, 129, 129, 129, 66, 36, 24) 'display heart symbol

Once you've got a character displaying using "manual" code then, depending on how many different characters you plan to display, you can either code up the rest of them manually as well, or put some effort into working out how to use the library's character generator code.

edit: Your display might be wired up with bytes as columns rather than as rows. If it is wired up as columns, then your heart will be rotated 90 degrees. One solution is to physically rotate the display 90 degrees so that your heart is upright. Or you could change the wiring. Or you could recalculate those byte values, but: your life will be much easier if the display is arranged in the same format as binary numbers, per the example above.

https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf

thanks.
how can I use setchar ?

 

[emexes]

how can I use setchar ?

Sorry, I don't know. Should be in the library documentation. There was an early indication that "This is an ESP8266 library, it will not work on Arduino" so that might be an issue too.

If you don't want to roll your own code, then another possibility is:

https://www.b4x.com/android/forum/threads/spi-i2c.66420/#post-464711