hello!!
i have just learned about mac usb driver programming and have
encounteredsome problems thus could anyone help me out here?
i am currently developing a usb driver for a webcam. My question is how do
i
store the data of the webcam into a buffer after sending a control message?
the control message is send thru control pipe while pipe one is used to
read
the data. do i send the control message over and then use a while loop to
read the data and then store it into the buffer??
any opinon,views or help will be greatly appreciated!
thks!
code: do i do it like this?
void downLoadImage(IOUSBInterfaceInterface **interface,int size)
//size-> refers to the size of the
{
picture
UInt8 buffer[size];
kern_return_t kernResult;
// int msg =0x1f500140;
IOUSBDevRequest req;
req.bmRequestType = USBmakebmRequestType(kUSBOut,
kUSBVendor,kUSBDevice);
req.bRequest=0x1;
req.wValue=0x9300;
req.wIndex=0;
req.wLength=0;
// req.pData=msg;
kernResult=(*interface)->ControlRequest(interface,0,&req);
if (kernResult != kIOReturnSuccess)
{
//printf("Unable to perform bulk write (%08x)\n",
kernResult);
(void) (*interface)->USBInterfaceClose(interface);
(void) (*interface)->Release(interface);
}
printf("downloading Image\n");
UInt32 numBytesRead;
numBytesRead = sizeof(gReadBuffer) - 1;
while(sizeof(gReadBuffer)!=size)
{
IOReturn kernaResult = (*interface)->ReadPipe( interface,
1,
gReadBuffer,&numBytesRead);
if (kernaResult != kIOReturnSuccess)
{
printf("Unable to perform bulk read (%08x)\n",
kernResult);
(void) (*interface)->USBInterfaceClose(interface);
(void) (*interface)->Release(interface);
//break;
}
printf("image dled %s (%ld bytes) from bulk endpoint\n",
gReadBuffer);
}
}
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