MT2503D串口调试指南：硬件接线与过程解析

mt2503d用UART输出调试信息的方法：
1.修改custom\common\hal\nvram\nvram_data_items.c，注意后面有中文注释的行
static port_setting_struct const NVRAM_EF_PORT_SETTING_DEFAULT[]=
{
    {
    #if defined (WISDOM_MMI) || defined(NEPTUNE_MMI)
        0,   /* tst-ps uses uart_port2(value is 1) */
        1,   /* APP uses uart_port1 (value is 0) */
    #elif defined(__DUAL_TALK_MODEM_SUPPORT__)
        0,   /* tst-ps uses uart_port1 */
        1,   /* APP uses uart_port2 */
    #elif defined(__USB_MULTIPLE_COMPORT_SUPPORT__) && defined(__L4_INIT_MULTIUSB_COM__)
        0,   /* TST-PS uses uart_port1 */
        5,   /* ATCI uses uart_port_usb2 */
    #else
        0,   /* tst-ps uses uart_port_null(value is 99) */这里改成0，即为UART1
        99,   /* APP uses uart_port1 (value is 0) */99意思是关闭
    #endif

    #if defined(EMPTY_MMI)
        921600, /* tst default baud rate for project without MMI */
    #elif defined (WISDOM_MMI)
/* under construction !*/
#elif defined(__USB_MULTIPLE_COMPORT_SUPPORT__) && defined(__L4_INIT_MULTIUSB_COM__)
921600, /* TST-PS baud uses 921600 */
    #else
        115200, /* tst default baud rate base = 115200 = 0x0001C200 */这里是波特率，catcher中的设置要跟这里一致
    #endif

    #if defined (__PS_SERVICE__)