main.cpp

00001 /* nucleo_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 "max7219.h" //此头文件未使用
00010  SPI spi(D11, D12, D13);          // Arduino compatible MOSI, MISO, SCLK
00011 //nucleo MOSI, MISO, SCLK
00012 //      PTD2, PTD3, PTD1   
00013 DigitalOut cs(D10);                // Chip select
00014 
00015 const unsigned char led1[]= {
00016     0x0,0x66,0x99,0x81,0x42,0x24,0x18,0x0
00017 };  //心
00018 const unsigned char led2[]= {
00019     0x3C,0x24,0x24,0xFF,0xFF,0x24,0x24,0x3C
00020 };  //中
00021 
00022 /// Send two bytes to SPI bus
00023 void SPI_Write2(unsigned char MSB, unsigned char LSB)
00024 {
00025     cs = 0;                         // Set CS Low
00026     spi.write(MSB);                 // Send two bytes
00027     spi.write(LSB);
00028     cs = 1;                         // Set CS High
00029 }
00030 
00031 /// MAX7219 initialisation
00032 void Init_MAX7219(void)
00033 {
00034     SPI_Write2(0x09, 0x00);         // Decoding off
00035     SPI_Write2(0x0A, 0x08);         // Brightness to intermediate
00036     SPI_Write2(0x0B, 0x07);         // Scan limit = 7
00037     SPI_Write2(0x0C, 0x01);         // Normal operation mode
00038     SPI_Write2(0x0F, 0x0F);         // Enable display test
00039     wait_ms(500);                   // 500 ms delay
00040     SPI_Write2(0x01, 0x00);         // Clear row 0.
00041     SPI_Write2(0x02, 0x00);         // Clear row 1.
00042     SPI_Write2(0x03, 0x00);         // Clear row 2.
00043     SPI_Write2(0x04, 0x00);         // Clear row 3.
00044     SPI_Write2(0x05, 0x00);         // Clear row 4.
00045     SPI_Write2(0x06, 0x00);         // Clear row 5.
00046     SPI_Write2(0x07, 0x00);         // Clear row 6.
00047     SPI_Write2(0x08, 0x00);         // Clear row 7.
00048     SPI_Write2(0x0F, 0x00);         // Disable display test
00049     wait_ms(500);                   // 500 ms delay
00050 }
00051 
00052 int main()
00053 {
00054     cs = 1;                         // CS initially High
00055     spi.format(8,0);                // 8-bit format, mode 0,0
00056     spi.frequency(1000000);         // SCLK = 1 MHz
00057     Init_MAX7219();                 // Initialize the LED controller
00058     
00059     while (1) {
00060         for(int i=1; i<9; i++)      // Write first character (8 rows)
00061             SPI_Write2(i,led1[i-1]);
00062         wait(1);                    // 1 sec delay
00063         for(int i=1; i<9; i++)      // Write second character
00064             SPI_Write2(i,led2[i-1]);
00065         wait(1);                    // 1 sec delay
00066     }
00067 }