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 "MMA8451Q.h"
00010 
00011 PinName const SDA = PTE25;
00012 PinName const SCL = PTE24;
00013  
00014 SPI spi(PTD2, PTD3, PTD1);          // Arduino compatible MOSI, MISO, SCLK
00015 DigitalOut cs(PTD0);                // Chip select
00016 
00017 #define MMA8451_I2C_ADDRESS (0x1d<<1)
00018  
00019 const unsigned char led1[]= {
00020     0xFF,0xB4,0x15,0xD1,0x85,0xB5,0x95,0xFF
00021 };  //H
00022 const unsigned char led2[]= {
00023     0x1F,0x60,0x80,0x40,0x40,0x80,0x60,0x1F
00024 };  //W
00025  
00026 /// Send two bytes to SPI bus
00027 void SPI_Write2(unsigned char MSB, unsigned char LSB)
00028 {
00029     cs = 0;                         // Set CS Low
00030     spi.write(MSB);                 // Send two bytes
00031     spi.write(LSB);
00032     cs = 1;                         // Set CS High
00033 }
00034 
00035 void direction(float x, float y){
00036     if(x > 0.5){
00037         printf("Left \n");
00038     }else if(x < -0.5){
00039         printf("Right \n");
00040     }else if(y > 0.5){
00041         printf("Up \n");
00042     }else if(y < -0.5){
00043         printf("Down \n");
00044     }else{
00045         printf("Neutral Position \n");    
00046       }
00047 }
00048  
00049 /// MAX7219 initialisation
00050 void Init_MAX7219(void)
00051 {
00052     SPI_Write2(0x09, 0x00);         // Decoding off
00053     SPI_Write2(0x0A, 0x08);         // Brightness to intermediate
00054     SPI_Write2(0x0B, 0x07);         // Scan limit = 7
00055     SPI_Write2(0x0C, 0x01);         // Normal operation mode
00056     SPI_Write2(0x0F, 0x0F);         // Enable display test
00057     wait_ms(500);                   // 500 ms delay
00058     SPI_Write2(0x01, 0x00);         // Clear row 0.
00059     SPI_Write2(0x02, 0x00);         // Clear row 1.
00060     SPI_Write2(0x03, 0x00);         // Clear row 2.
00061     SPI_Write2(0x04, 0x00);         // Clear row 3.
00062     SPI_Write2(0x05, 0x00);         // Clear row 4.
00063     SPI_Write2(0x06, 0x00);         // Clear row 5.
00064     SPI_Write2(0x07, 0x00);         // Clear row 6.
00065     SPI_Write2(0x08, 0x00);         // Clear row 7.
00066     SPI_Write2(0x0F, 0x00);         // Disable display test
00067     wait_ms(500);                   // 500 ms delay
00068 }
00069  
00070 int main()
00071 {
00072     
00073     cs = 1;                         // CS initially High
00074     spi.format(8,0);                // 8-bit format, mode 0,0
00075     spi.frequency(1000000);         // SCLK = 1 MHz
00076     Init_MAX7219();                 // Initialize the LED controller
00077     MMA8451Q acc(SDA, SCL, MMA8451_I2C_ADDRESS);
00078     unsigned char row = 0x03;
00079     
00080             unsigned char position[] = {
00081             0x00,0x00,0x80,0x00,0x00,0x00,0x00,0x00
00082             };
00083     
00084      for(int i=1; i<9; i++)      // Write first character (8 rows)
00085             SPI_Write2(i,led1[i-1]);
00086     while (1) {
00087 
00088         float x, y;
00089         x = acc.getAccX();
00090         y = acc.getAccY();
00091         
00092     if(x > 0.5){
00093         printf("Left \n");
00094         position[1] = position[1]*2;
00095     }else if(x < -0.5){
00096         printf("Right \n");
00097         position[1] = position[1]/2;
00098     }else if(y > 0.5){
00099         printf("Up \n");
00100         position[0] = position[0]-1;
00101         row--;
00102     }else if(y < -0.5){
00103         printf("Down \n");
00104         position[0] = position[0]+1;
00105         row++;
00106         }
00107 
00108 
00109        
00110         wait(1);                    // 1 sec delay
00111         SPI_Write2(position[0], position[1]);
00112          for(int i=1; i<9; i++){      // Write first character (8 rows)
00113                 if(i != row){
00114          SPI_Write2(i,led1[i-1]);
00115          }
00116         }
00117     }
00118     
00119     
00120 }