max7219

A library for the MAX7219 7 segment 8 digit display with decimals.

An easy to use library that allows you to write to the display, using the DisplayText method.

DisplayText(Text, Justification)

• Text : The text you want to display (8 characters or less, plus up to 8 decimals)
• Justification : Left or right justified. LEFT(0) or RIGHT(1).

e.g.:

max7219.DisplayText("HELLO", LEFT);

Including decimals in the text will automatically take care of decimals like this:

e.g.

max7219.DisplayText("96.78F", RIGHT);

Write to specific digits on the display using the DisplayChar method:

DiaplayChar(Digit, Char, Decimal)

• Digit : represents the digit number 0-7 (Rightmost Digit = 7, Leftmost Digit = 0)
• Char : The character to display
• Decimal : A flag to illuminate the decimal (true/false)

e.g.

max7219.DisplayChar(5, 'L', false);

Create your own fonts and symbols

A font library is included but can be modified by editing the max7219.h file.

*********************************************************************************************************
* LED Segments:         a
*                     ----
*                   f|    |b
*                    |  g |
*                     ----
*                   e|    |c
*                    |    |
*                     ----  o dp
*                       d
*   Register bits:
*      bit:  7  6  5  4  3  2  1  0
*           dp  a  b  c  d  e  f  g
*********************************************************************************************************
* Example : The letter 'I' is represented by illuminating LED's 'b' and 'c' (refer above diagram)
*           Therfore the binary representation of 'I' is as follows
*
*           abcdefg
*           0110000
* 
*           The table below contains all the binary values for the desired font. New font characters
*           can be added or altered as required. 
*           
*           The DP bit is used to switch on the decimal place LED. DP is not included in the below table
*           but is added in the register within the libary depending on the content being displayed.  
*********************************************************************************************************

static const struct {
    char   ascii;
    char   segs;
} MAX7219_Font[] = {
  {'A',0b1110111},{'B',0b1111111},{'C',0b1001110},{'D',0b1111110},{'E',0b1001111},{'F',0b1000111},       
  {'G',0b1011110},{'H',0b0110111},{'I',0b0110000},{'J',0b0111100},{'L',0b0001110},{'N',0b1110110},       
  {'O',0b1111110},{'P',0b1100111},{'R',0b0000101},{'S',0b1011011},{'T',0b0001111},{'U',0b0111110},       
  {'Y',0b0100111},{'[',0b1001110},{']',0b1111000},{'_',0b0001000},{'a',0b1110111},{'b',0b0011111},       
  {'c',0b0001101},{'d',0b0111101},{'e',0b1001111},{'f',0b1000111},{'g',0b1011110},{'h',0b0010111},       
  {'i',0b0010000},{'j',0b0111100},{'l',0b0001110},{'n',0b0010101},{'o',0b1111110},{'p',0b1100111},       
  {'r',0b0000101},{'s',0b1011011},{'t',0b0001111},{'u',0b0011100},{'y',0b0100111},{'-',0b0000001},
  {' ',0b0000000},{'0',0b1111110},{'1',0b0110000},{'2',0b1101101},{'3',0b1111001},{'4',0b0110011},
  {'5',0b1011011},{'6',0b1011111},{'7',0b1110000},{'8',0b1111111},{'9',0b1111011},{'/0',0b0000000},
  };