c++ - 错误[P​​e167] : argument of type "uint16_t *" is incompatible with parameter of type "unsigned char *"

Question

我想通过usb建立平板电脑和stm32之间的通信，为此我在代码中添加了usb库。在代码中添加库时，我收到此错误。

错误[Pe167]:“uint16_t *”类型的参数与“unsigned char *”类型的参数不兼容

我正在使用 IAR Embedded Workbench EWARM 工具进行 stm32 编码。如下所示的函数返回行出现错误。

static USBH_Status USBH_ADK_getProtocol ( USB_OTG_CORE_HANDLE *pdev, USBH_HOST *phost)
{
phost->Control.setup.b.bmRequestType = USB_D2H | USB_REQ_TYPE_VENDOR | USB_REQ_RECIPIENT_DEVICE;
phost->Control.setup.b.bRequest = ACCESSORY_GET_PROTOCOL;
phost->Control.setup.b.wValue.w = 0;
phost->Control.setup.b.wIndex.w = 0;
phost->Control.setup.b.wLength.w = 2;
 abc= ADK_Machine.protocol;
/* Control Request */
return USBH_CtlReq(pdev, phost, &ADK_Machine.protocol , 2 );
}

USBH_CtlReq函数是

USBH_Status USBH_CtlReq     (USB_OTG_CORE_HANDLE *pdev, 
                         USBH_HOST           *phost, 
                         uint8_t             *buff,
                         uint16_t            length)
{
USBH_Status status;
status = USBH_BUSY;

switch (phost->RequestState)
{
case CMD_SEND:
/* Start a SETUP transfer */
USBH_SubmitSetupRequest(phost, buff, length);
phost->RequestState = CMD_WAIT;
status = USBH_BUSY;
break;

case CMD_WAIT:
 if (phost->Control.state == CTRL_COMPLETE ) 
{
  /* Commands successfully sent and Response Received  */       
  phost->RequestState = CMD_SEND;
  phost->Control.state =CTRL_IDLE;  
  status = USBH_OK;      
}
else if  (phost->Control.state == CTRL_ERROR)
{
  /* Failure Mode */
  phost->RequestState = CMD_SEND;
  status = USBH_FAIL;
}   
 else if  (phost->Control.state == CTRL_STALLED )
{
  /* Commands successfully sent and Response Received  */       
  phost->RequestState = CMD_SEND;
  status = USBH_NOT_SUPPORTED;
}
break;

default:
break; 
}
return status;
}

任何人都可以帮我解决这个问题吗？提前致谢。

Answer 1

AFAICT，行中:

return USBH_CtlReq(pdev, phost, &ADK_Machine.protocol , 2 );

ADK_Machine.protocol 是一个 uint16_t。如果这是真的，那么获取其地址将产生一个 uint16_t *，它无法转换为 USBH_CtlReq 期望的 uint8_t*。

C 中的许多低级“发送”函数将参数声明为 uint8_t* 或 unsigned char*，以表明它们需要“字节”。原则上，他们也可以声明 void*。

但是，在这种情况下，唯一要做的就是强制转换，例如:

return USBH_CtlReq(pdev, phost, (uint8_t*)&ADK_Machine.protocol , 2 );

当然，您需要注意这不会考虑字节顺序。