Re: [Libusb-devel] Control transfer doubt

[Felipe B. <me...@fe...>]

Hi,

On 08/17/2010 12:06 PM, Thejus.. wrote:
> Hi
> 
>      I want to feed in the values for libusb_control_transfer().But i am not
> able to get how to input the values for bRequest,wValue,wLength.
> 
> This is control transfer where i am loading some seed value into some
> register address,I don't know how to fill in the fields of
> libusb_control_transfer to make it work.
> 
> 
> bmRequestType=LIBUSB_ENDPOINT_IN|LIBUSB_REQUEST_TYPE_CLASS|LIBUSB_RECIPIENT_DEVICE
> 
> But my register address is 320 which i am feeding to
> setup_data[39:8](control transfer). Here 8 bits of bRequest,16 bits of
> wValue and 8 bit LSB of wIndex comes into picture.

have you checked the documentation ?

here's the prototype for that function:

int 	libusb_control_transfer  (libusb_device_handle  *dev_handle,
uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t
wIndex, unsigned char *data, uint16_t wLength, unsigned int timeout)


so, for example a SET_FEATURE would be:

libusb_control_transfer(udevh, LIBUSB_RECIPIENT_DEVICE |
LIBUSB_REQUEST_TYPE_STANDARD, LIBUSB_REQUEST_SET_FEATURE, TEST_MODE,
(testnumber << 8), NULL, 0, 1000);

-- 
balbi