我们要用到的工具是C-kermit 和 dnw2。其中C-kermit是串口连接程序。而dnw2是用来向开发板下载程序的。
首先我们安装kermit，我们可以使用#sudo apt-get install ckermit来安装kermit。

下载完成之后还要对其进行配置。

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#sudo vim /etc/kermit/kermrc

Alt text

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set line /dev/ttyUSB0 (这里填写通过命令#dmesg看到的设备名。上图中红线部分。attached to ttyUSB0 说明已经附加到了ttyUSB0这个设备上了。)
set speed 115200
set carrier-watch off
set handshake none
set flow-control none
robust
set file type bin
set file name lit
set rec pack 1000
set send pack 1000
set window 5

配置完以后的样子

Alt text

红色方框内的内容为添加内容。

使用以下命令打开kermit：

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#sudo kermit

使用以下命令链接：

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>connect

就可以使用串口了。

切换：按下Ctrl+\ ,再按c 就跳回kermit。跳回串口控制，可以输入c,即connect命令。

Alt text

上图是使用kermit连接开发板。

接着说一下dnw2的使用。先把以下某大神写的代码保存成文件dnw2.c

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#include <stdio.h>
#include <usb.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define QQ2440_SECBULK_IDVENDOR        0x5345
#define QQ2440_SECBULK_IDPRODUCT    0x1234
struct usb_dev_handle * open_port() {
    struct usb_bus *busses, *bus;
    usb_init();
    usb_find_busses();
    usb_find_devices();
    busses = usb_get_busses();
    for (bus = busses; bus; bus = bus->next) {
        struct usb_device *dev;
        for (dev = bus->devices; dev; dev = dev->next) {
            printf("idVendor:0x%x\t,ipProduct:0x%x\n",
                    dev->descriptor.idVendor, dev->descriptor.idProduct);
            if (QQ2440_SECBULK_IDVENDOR == dev->descriptor.idVendor
                    && QQ2440_SECBULK_IDPRODUCT == dev->descriptor.idProduct) {
                printf("Target usb device found!\n");
                struct usb_dev_handle *hdev = usb_open(dev);
                if (!hdev) {
                    perror("Cannot open device");
                } else {
                    if (0 != usb_claim_interface(hdev, 0)) {
                        perror("Cannot claim interface");
                        usb_close(hdev);
                        hdev = NULL;
                    }
                }
                return hdev;
            }
        }
    }
    printf("Target usb device not found!\n");
    return NULL;
}
void usage() {
    printf("Usage: dnw2 <file>\n\n");
}
unsigned char* prepare_write_buf(char *filename, unsigned int *len) {
    unsigned char *write_buf = NULL;
    struct stat fs;
    int fd = open(filename, O_RDONLY);
    if (-1 == fd) {
        perror("Cannot open file");
        return NULL;
    }
    if (-1 == fstat(fd, &fs)) {
        perror("Cannot get file size");
        goto error;
    }
    write_buf = (unsigned char*) malloc(fs.st_size + 10);
    if (NULL == write_buf) {
        perror("malloc failed");
        goto error;
    }
    if (fs.st_size != read(fd, write_buf + 8, fs.st_size)) {
        perror("Reading file failed");
        goto error;
    }
    printf("Filename : %s\n", filename);
    printf("Filesize : %d bytes\n", fs.st_size);
    *((u_int32_t*) write_buf) = 0x30000000; //download address
    *((u_int32_t*) write_buf + 1) = fs.st_size + 10; //download size;
    *len = fs.st_size + 10;
    return write_buf;
    error: if (fd != -1)
        close(fd);
    if (NULL != write_buf)
        free(write_buf);
    fs.st_size = 0;
    return NULL;
}
int main(int argc, char *argv[]) {
    if (2 != argc) {
        usage();
        return 1;
    }
    struct usb_dev_handle *hdev = open_port();
    if (!hdev) {
        return 1;
    }
    unsigned int len = 0;
    unsigned char* write_buf = prepare_write_buf(argv[1], &len);
    if (NULL == write_buf)
        return 1;
    unsigned int remain = len;
    unsigned int towrite;
    printf("Writing data ...\n");
    while (remain) {
        towrite = remain > 512 ? 512 : remain;
        if (towrite != usb_bulk_write(hdev, 0x03, write_buf + (len - remain),
                towrite, 3000)) {
            perror("usb_bulk_write failed");
            break;
        }
        remain -= towrite;
        printf("\r%d%\t %d bytes     ", (len - remain) * 100 / len, len
                - remain);
        fflush(stdout);
    }
    if (0 == remain)
        printf("Done!\n");
    return 0;
}

然后安装 libusb 库#sudo apt-get install libusb-dev

编译 dnw2.c 文件#gcc dnw2.c -o dnw2 -lusb

把生成的可执行文件 dnw2 移动到 /opt/dnw 里面#sudo mv dnw2 /opt/dnw

以root权限打开#sudo vim /etc/profile

在文件末尾加上export PATH=$PATH:/opt/dnw

保存退出后运行命令#source /etc/profile

PC 链接 TQ2440开发板，在终端里面运行 #sudo kermit ，然后connect连接，打开串口，按相应键进入 USB 传输

再开一个终端，输入#sudo dnw2 <文件完整路径>

等待下载完毕。

参考链接：

linux环境下安装dnw（for mini2440）
mini2440 在 ubuntu12.04 下 minicom 串口 dnw2 实验成功