Tutorial-3: Adding Custom English Font in OLED Display

1. Introduction

                 In the previous tutorial, we displayed a 12x24 matrix on OLED display. In this tutorial, we will display English font on OLED. We will create Hex code for English font in GLCD Font Creator. 

 Please Video of this on Youtube:

 

2. Creating Hex code For Font

Steps to create a custom font for OLED are as follows:

     1)   Open GLCD Font creator

     2)   Goto File->New Font-> Import An Existing System Font

     

        3)   Following window will open. I am selecting  

                                Font  -> @DFGothic-EB font ,

                        Font style ->  Regular

                            Size      ->  18

                    

      

      4)   We want to input the ASCII code of start and last character:

              

      5)   Following window will open. Now click on 'Export for GLCD'

           

         

         6) In following windows 1)select mikroC 2) then copy full array in between two  curly braces { }.

  

      

Storing Array in Flash memory:

          In the following image, we calculated the number of bytes required for storing a single character Hex code

          37bytes are require for storing single character's Hex code

           

          No. of characters we want to display = 127-31= 96

                                                                     

          No. of bytes required for 96 characters = 96 x 37 = 3552 byte

           But SRAM of Microcontroller ( Arduino in this case) is 2 kb i.e 2048 bytes

                                                                        

          So we will store our Hex code array in Flash memory which is 32kb in Arduino. It is done using PROGMEM as follows:

                 const PROGMEM dataType variableName[] = {};    

 Also, you need to know the first character is represented by first 37 items in an array and their index are from 0 to 36 in which the first number does not represent any pixel. Next character is represented by items with index 37-73 as shown in following image.

    The following function 
          1) takes input as a character, x and y position
          2) finds line no. in array ( as shown in above image)
          3) Finds the index of item from which hex code of character to be displayed is started and add 1 because first Hex no. does not represent any pixel
       

       

      To Print string we need to call above function in a loop and also each time we need to shift cursor by character width to print next character in at next location on the screen. Following code implement the same
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