关于atmega32u4的CDC模拟串口程序

编程环境使用的是AVR studio

下载程序在这个链接里https://www.pjrc.com/teensy/usb_serial.html

关键是电脑要安装驱动才能正常通信

include <avr/io.h>
#include <avr/pgmspace.h>
#include <stdint.h>
#include <util/delay.h>
#include <stdio.h>
#include <string.h>
#include "usb_serial.h"


#define LED_CONFIG    (DDRD |= (1<<6))
#define LED_ON        (PORTD |= (1<<6))
#define LED_OFF        (PORTD &= ~(1<<6))
#define CPU_PRESCALE(n) (CLKPR = 0x80, CLKPR = (n))

void send_str(const char *s);

int main(void)
{
    CPU_PRESCALE(0);
    
    LED_CONFIG;//输出拉低
    LED_OFF;

    usb_init();

    while(1)
    {
        unsigned char buffer[3] = {0};
        
        int n = usb_serial_available();//获取缓存区中的字节数
    
        if(n>3 || (n<3 && n!=0))
        {
            send_str(PSTR(" please enter 3 words
"));        
            n = 0;
            usb_serial_flush_input();
        }
        else
        {
            for(int i = 0;i<n;i++)
            {
                int m = usb_serial_getchar();
                if(m>=0)
                {
                    buffer[i] = m;
                }
            }
        }
        if (buffer[0]== 0xAA && buffer[2] == 0x55)
        {
            switch(buffer[1])
            {
                case 0x31:

                //    DDRD |= (1<<6);//输出拉高
                //    LED_ON;
                    send_str(PSTR(" OPEN RHP-260+
"));
                break;

                case 0x32:

                //    DDRD |= (1<<6);//输出拉低
                //    LED_OFF;
                    memset(buffer,0,3);
                    send_str(PSTR(" OPEN RHP-700+
"));
                break;
            
                default:
                    usb_serial_putchar(buffer[1]);
                    send_str(PSTR(" wrong
"));
                    memset(buffer,0,3);
                break;
            }
        }
    }
}

// Send a string to the USB serial port.  The string must be in
// flash memory, using PSTR
//
void send_str(const char *s)
{
    char c;
    while (1) {
        c = pgm_read_byte(s++);
        if (!c) break;
        usb_serial_putchar(c);
    }
}

头文件usb_serial.h和usb_serial.c 是使用上面网页下载的，没有改动，只改了主函数，串口指令控制点灯