I want to establish communication between tablet and stm32 via usb, for which i had added usb libraries in the code. On adding libraries in code i got this error.
Error[Pe167]: argument of type "uint16_t *" is incompatible with parameter of type "unsigned char *"
I am using IAR Embedded Workbench EWARM Tool for stm32 coding.Error is comming on return line of function shown below.
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 );
}
And the function USBH_CtlReq is
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;
}
can any one please help me in solving this problem.Thanks in advance.
AFAICT, in the line:
return USBH_CtlReq(pdev, phost, &ADK_Machine.protocol , 2 );
the ADK_Machine.protocol is an uint16_t. If that's true, than, taking its address will yield a uint16_t *, which is not convertible to uint8_t* that USBH_CtlReq expects.
A lot of low-level "sending" functions in C declare arguments as uint8_t* or unsigned char*, to indicate that they are expecting "bytes". In principle, they could just as well declare void*.
But, in this case, the only thing to do is cast, like:
return USBH_CtlReq(pdev, phost, (uint8_t*)&ADK_Machine.protocol , 2 );
Of course, you need to be mindful that this will not take care of endianness.
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