main.cpp

00001 /* 06_spi_max7219_led8x8
00002  *
00003  * Simple demo to drive a 8x8-as LED matrix by a MAX7219 LED driver IC
00004  * After initialisation two characters (H and W) are displayed alternatively.
00005  * The MAX7219 IC is driven by hardware SPI: SPI0 module at PTD1, PTD2, PTD3.
00006  */
00007 
00008 #include "mbed.h"
00009 #include "lib_matrix.h"
00010 #include "ascii_char_h.h"
00011 
00012 SPI spi(D11,D12,D13);          // Arduino compatible MOSI, MISO, SCLK
00013 DigitalOut cs(D14);
00014 
00015 void MAX7219_init(char noChips)
00016 {
00017     cs = 1;                         // CS initially High
00018     spi.format(8,0);                // 8-bit format, mode 0,0
00019     spi.frequency(1000000);         // SCLK = 1 MHz
00020     while(noChips)
00021         MAX7219_config(--noChips);
00022 }
00023 //------------------------------------------------------------------------------
00024 void MAX7219_config(char chip)
00025 {
00026     MAX7219_write(DECODE_MODE_REG,DISABLE_DECODE,chip);
00027     MAX7219_write(INTESITY_REG,BRIGHTNESS,chip);
00028     MAX7219_write(SCAN_LIMIT_REG,SCAN_ALL_DIGITS,chip);
00029     MAX7219_write(SHUTDOWN_REG,NORMAL_OPERATION,chip);
00030     MAX7219_write(DISPLAY_TEST_REG,DISABLE_TEST,chip);
00031 }
00032 //------------------------------------------------------------------------------
00033 void MAX7219_write(char regName,char data,char chip)
00034 {
00035     cs = 0;
00036 
00037     spi.write(regName);
00038     spi.write(data);
00039     while(chip--)
00040         MAX7219_NoOperation();        //Used for daisy chained (Cascaded) arrangements
00041 
00042     cs = 1;
00043 }
00044 //------------------------------------------------------------------------------
00045 void MAX7219_displayText(char* text)
00046 {
00047     char chip = 0;
00048 
00049     while(*text) {
00050         char row = (*text++) - 32;//(Text-32)...because the first 32 ASCII character codes are none Printable (control chars)
00051 
00052         for(int col = 0; col < 8; col++) {
00053             MAX7219_write( col+1, symbol_h[row][col], chip );
00054         }
00055 
00056         chip++;
00057     }
00058 }
00059 void MAX7219_displayText(char* text, char indice, char nb_chip)
00060 {
00061     char chip = 0;
00062     char * current_pointer;
00063     current_pointer=text+indice;
00064     while(chip<nb_chip) {
00065         char row = (*current_pointer++) - 32;//(Text-32)...because the first 32 ASCII character codes are none Printable (control chars)
00066         for(int col = 0; col < 8; col++) {
00067             MAX7219_write( col+1, symbol_h[row][col], chip );
00068         }
00069         chip++;
00070     }
00071 }
00072 void MAX7219_display(unsigned const char led[], char no_chip)
00073 {
00074     for(int col = 0; col < 8; col++) {
00075         MAX7219_write( col+1, led[col], no_chip );
00076     }
00077 }
00078 //-----------Passes the data to the adjacent MAX7219 in the Daisy Chain---------
00079 void MAX7219_NoOperation()
00080 {
00081     spi.write(NO_OP_REG);
00082     spi.write(0x00);                //Don't care (Can be any arbitrary value)
00083 }
00084 
00085 int main()
00086 {
00087     MAX7219_init(4);
00088     while(1) {
00089         MAX7219_displayText("ABCD");
00090         wait(2);
00091         MAX7219_displayText("HELL");
00092         wait(2);
00093         MAX7219_display(led_blank,0);
00094         MAX7219_display(led_heart,1);
00095         MAX7219_display(led_heart,2);
00096         MAX7219_display(led_blank,3);
00097         wait(2);
00098         for(int i=0;i<7;i++){
00099             MAX7219_displayText("HELLO WORLD",i,4);
00100             wait(2);
00101         }
00102     }
00103 
00104 }