Is possible extend font about diacritical?
ščťžýáíéľúôňď

Yes, the characters are defined in the code as constants. You will need to make your own data for the new characters and include them.

Already know how to forms characters. Expanded I'm font about new characters. I hope, as though it will function.

It's very simple, each line represents a character using 5 byte values, for example:

0x7E,0x11,0x11,0x11,0x7E,0x00, // 65 = A

So the bytes are the columns of the character:

00111110 = 0x7E
00010001 = 0x11
00010001 = 0x11
00010001 = 0x11
00111110 = 0x7E
00000000 = 00x0

All characters are 8 pixels high by 5 pixels across followed by one column of space.

New charakters:
0x20,0x54,0x56,0x55,0x78,0x00, // 130 = á

0x38,0x45,0x46,0x45,0x00,0x00, // 131 = č
0x38,0x44,0x44,0x48,0x7F,0x03, // 132 = ď
0x38,0x54,0x56,0x55,0x18,0x00, // 133 = é
0x00,0x44,0x7E,0x45,0x00,0x00, // 134 = í
0x00,0x41,0x7F,0x42,0x01,0x00, // 135 = ľ
0x7C,0x09,0x06,0x05,0x78,0x00, // 136 = ň
0x38,0x44,0x46,0x45,0x38,0x00, // 137 = ó
0x7C,0x08,0x06,0x05,0x08,0x00, // 138 = ŕ
0x48,0x55,0x56,0x55,0x20,0x00, // 139 = š
0x04,0x3F,0x45,0x42,0x21,0x00, // 140 = ť
0x3C,0x40,0x42,0x21,0x7C,0x00, // 141 = ú
0x0C,0x90,0x92,0x91,0x7C,0x00, // 142 = ý
0x44,0x65,0x56,0x4D,0x44,0x00, // 143 = ž
0x38,0x46,0x45,0x46,0x38,0x00, // 144 = ô

Mplab write:
Error [228] D:\Downloads\16x8 LED Matrix Display\16x8_LED_Display sk\main.c; 116.19 illegal character (0xFA)
Error [228] D:\Downloads\16x8 LED Matrix Display\16x8_LED_Display sk\main.c; 166.19 illegal character (0xE1)
Error [228] D:\Downloads\16x8 LED Matrix Display\16x8_LED_Display sk\main.c; 169.19 illegal character (0xF2)
Error [228] D:\Downloads\16x8 LED Matrix Display\16x8_LED_Display sk\main.c; 270.17 illegal character (0xBE)

What now?
Be somewhere yet behind-defined by number charakters?

In this way it will not display:

case 7: strcat(string, "Nedeľa ");

case 1: strcat(string, "Január ");

strcat(message, " ľščťžýáíéúňô ");

When cancel diacritical so it will display.
Know why the deal appears diacritical?

You have to make sure that your new characters are mapped correctly. If I remember rightly the code uses the ASCII value of the characters in the passed string to get the right point in the character definition array.

You will need to alter the mapping code to make sure it selects the right thing when your new characters are passed.

Solved I'm it.To the strings will not arrange write down character with diacritical. It is possible however insert directly character code. Then it writes diacritical.
Instance:
displayScrollText(" D\x87tum: ");

write: Dátum

Great Glad you got it working, and it's a good tip too!

Hello, I'm having trouble compiling files that will be
I can provide files hex?