2015年12月7日 (一) 21:35的版本

1 编译布局

   #include <stdio.h>
    #include <fcntl.h>       /* File Control Definitions           */
    #include <termios.h>     /* POSIX Terminal Control Definitions */
    #include <unistd.h>      /* UNIX Standard Definitions          */ 
    #include <errno.h>       /* ERROR Number Definitions           */
    #include <sys/ioctl.h>   /* ioctl()                            */

    main(void)
    {
        int fd;     /*File Descriptor*/
        int status; 

        fd = open("/dev/ttyUSB0",O_RDWR | O_NOCTTY ); //Opening the serial port

        ioctl(fd,TIOCMGET,&status); /* GET the State of MODEM bits in Status */
        status |= TIOCM_RTS;        // Set the RTS pin
        ioctl(fd, TIOCMSET, status);

        getchar(); //To view the change in status pins before closing the port

        close(fd);
     }

int disableRTS ()
{
    char fd, ret, flags;

    // open device
    if ((fd = open("/dev/cu.mydevice", O_RDWR | O_NDELAY)) < 0)
    {
        fprintf(stderr, "failed to open device");
        return -1;
    }

    // Get the current state of the bits
    ioctl(fd, TIOCMGET, &flags);
    fprintf(stderr, "Flags are %x.\n", flags);    

    flags &= ~TIOCM_RTS;  // Disable the RTS bit
    ret = ioctl(fd, TIOCMSET, &flags);

    if (ret == -1)
        fprintf(stderr, "TIOCMSET failed\n");
    else
        fprintf(stderr, "TIOCMSET succeeded. flags: %x.\n", flags);

    return 0;
}

2 地址空间映射

/* RAM */
#define RAM_BASE		0x3FFE8000
#define RAM_SIZE		0x00018000	// Size: 98304 bytes
#define RAM_BIOS_DATA_BASE 	0x3FFFC000      // ROM-XTOS system data RAM. Size: 16384 bytes

/* IRAM */
#define IRAM_BASE		0x40100000
#define IRAM_SIZE		0x00008000	// Size: 32768 bytes

/* FLASH */
#define FLASH_BASE		0x40200000
#define FLASH_MIN_SIZE         	0x00080000	// 512 KB
#define FLASH_MAX_SIZE  	0x01000000      // 16 MB
#define FLASH_CACHE_MAX_SIZE	0x100000        // Size of Cached Flash

/* dport (io1) section */
#define DPORT_BASE		0x3ff00000

/* io2 section */
#define IO2_BASE		0x3ff20000	// Size: 6144 bytes

/* io3 section */
#define UART0_BASE		0x60000000
#define SPI1_BASE		0x60000100
#define SPI0_BASE		0x60000200
#define GPIO_BASE		0x60000300
#define HDRF_BASE		0x60000500
#define TIMER_BASE		0x60000600
#define RTC_BASE		0x60000700
#define IOMUX_BASE		0x60000800
#define WDT_BASE		0x60000900
#define SDIO_BASE		0x60000A00
#define SCL_BASE		0x60000B00
#define SAR_BASE		0x60000D00
#define I2S_BASE		0x60000E00
#define UART1_BASE		0x60000F00
#define RTC_RAM_BASE	        0x60001000	// Size: 1024 bytes
#define RTC_MEM_BASE	        0x60001100

/* io4 section */
#define IO4_BASE		0x60009800	// Size: 1536 bytes