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ARM®mbed OS 提高 之max7219 spi 8x8点阵显示 8x8点阵屏通过SPI连接 MAX7219,初始化之后交替显示心形和中字. 使用nucleo SPI接口 硬件:
/* nucleo_spi_max7219_led8x8 * * Simple demo to drive a 8x8-as LED matrix by a MAX7219 LED driver IC * After initialisation two characters (H and W) are displayed alternatively. * The MAX7219 IC is driven by hardware SPI: SPI0 module at PTD1, PTD2, PTD3. */ #include "mbed.h" //#include "max7219.h" //此头文件未使用 SPI spi(D11, D12, D13); // Arduino compatible MOSI, MISO, SCLK //nucleo MOSI, MISO, SCLK // PTD2, PTD3, PTD1 DigitalOut cs(D10); // Chip select const unsigned char led1[]= { 0x0,0x66,0x99,0x81,0x42,0x24,0x18,0x0 }; //心 const unsigned char led2[]= { 0x3C,0x24,0x24,0xFF,0xFF,0x24,0x24,0x3C }; //中 /// Send two bytes to SPI bus void SPI_Write2(unsigned char MSB, unsigned char LSB) { cs = 0; // Set CS Low spi.write(MSB); // Send two bytes spi.write(LSB); cs = 1; // Set CS High } /// MAX7219 initialisation 初始化 void Init_MAX7219(void) { SPI_Write2(0x09, 0x00); // Decoding off SPI_Write2(0x0A, 0x08); // Brightness to intermediate SPI_Write2(0x0B, 0x07); // Scan limit = 7 SPI_Write2(0x0C, 0x01); // Normal operation mode SPI_Write2(0x0F, 0x0F); // Enable display test wait_ms(500); // 500 ms delay SPI_Write2(0x01, 0x00); // Clear row 0. SPI_Write2(0x02, 0x00); // Clear row 1. SPI_Write2(0x03, 0x00); // Clear row 2. SPI_Write2(0x04, 0x00); // Clear row 3. SPI_Write2(0x05, 0x00); // Clear row 4. SPI_Write2(0x06, 0x00); // Clear row 5. SPI_Write2(0x07, 0x00); // Clear row 6. SPI_Write2(0x08, 0x00); // Clear row 7. SPI_Write2(0x0F, 0x00); // Disable display test wait_ms(500); // 500 ms delay } int main() { cs = 1; // CS initially High spi.format(8,0); // 8-bit format, mode 0,0 spi.frequency(1000000); // SCLK = 1 MHz Init_MAX7219(); // Initialize the LED controller while (1) { for(int i=1; i<9; i++) // Write first character (8 rows) SPI_Write2(i,led1[i-1]); wait(1); // 1 sec delay for(int i=1; i<9; i++) // Write second character SPI_Write2(i,led2[i-1]); wait(1); // 1 sec delay } } 源程序 
mbed-8x8.zip
(1.36 KB, 下载次数: 67)
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效果图
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