环境：STM32F103 + CH376S开发板 + USB扫码枪

问题: USB设备初始化过程失败，获取设备描述符返回0x15(USB_INT_CONNECT), 期望的是0x14(USB_INT_SUCCESS)

相关代码：

/* 等待INT中断*/

u8 waitUSBDeviceInterrupt(void) {

unsigned short i;

for ( i = 0; CH375_INT_WIRE != 0; i ++ ) {  // 如果CH375的中断引脚输出高电平则等待,通过计数防止超时

delay_us(1);

if ( i == 0xF000 )

{

xWriteCH376Cmd( CMD_ABORT_NAK ); 

printf("Wait device timeout, send cmd abort!\n");

}

}

xWriteCH376Cmd( CMD_GET_STATUS );  /* 产生操作完成中断, 获取中断状态 */

return( xReadCH376Data() );

}

/* 从设备端获取描述符 */

unsigned char get_descr( unsigned char type ) {  

xWriteCH376Cmd( CMD_GET_DESCR );

xWriteCH376Data( type );  /* 描述符类型, 只支持1(设备)或者2(配置) */

printf("write -->cmd=%x, type=%x\n",CMD_GET_DESCR, type);

return( waitUSBDeviceInterrupt() );

}

unsigned char init_scanner() {

#definep_dev_descr((PUSB_DEV_DESCR)buffer)

#definep_cfg_descr((PUSB_CFG_DESCR_LONG)buffer)

unsigned char status, len, c;

printf("init_scanner enter...\n");

status=get_descr(1);  /* 获取设备描述符 *///<<<<<<<<<<<<问题点<<<<<<<<<<<<<<<<<<<<

if ( status==USB_INT_SUCCESS ) {

           /*无法进入，因为get_descr（1）返回的是0x15*///<<<<<<<<<问题点<<<<<<<<<<<<<<<<<<<<

           ......

}

printf("get descr out, status=%#x\n",status);

return(status);

}

 /* 初始化CH376 */

u8mInitCH376Host( void ) 

{

u8res;

//IO init

CH375_Init();

//Check if CH376 coud work

xWriteCH376Cmd( CMD_CHECK_EXIST );

printf("xWriteCH376Cmd= %#x\n", CMD_CHECK_EXIST);

xWriteCH376Data( 0x55 );

res = xReadCH376Data( );

printf("xReadCH376Data= %#x\n", res);

if ( res != 0xAA ) return( CH376_ERR );

printf("set usb mode ---> 6\n");

set_usb_mode( 6 );

printf("wait usb device online...\n");

while ( waitUSBDeviceInterrupt()!=USB_INT_CONNECT ); 

#define USB_RESET_FIRST 0

#if USB_RESET_FIRST

printf("reset usb device...\n");

set_usb_mode( 7 );

delay_ms(10);

set_usb_mode( 6 );

delay_ms(100);

printf("wait usb device online again...\n");

while ( waitUSBDeviceInterrupt()!=USB_INT_CONNECT );

#endif

        delay_ms(200);

if ( init_scanner()!=USB_INT_SUCCESS ) while(1);

  return 0;

}

调试日志：

start

xWriteCH376Cmd= 0x6

xReadCH376Data= 0xaa

set usb mode ---> 6

wait usb device online...

init_scanner enter...

write -->cmd=46, type=1

get descr out, status=0x15 //<<<<<<<<<初始化过程终止<<<<<<<<<<<<<<<<<<<<