WinUSB: WinUsb_ControlTransfer - index filed in the setup packet is ignored or masked ???

Question

I am using WinUSB to communicate with my device only through control endpoint.  When I use WinUsb_ControlTransfer to send setup packet ( WINUSB_SETUP_PACKET Wsp = { 0x41, 0x60, 0x6, 0xFC, 0x4} ;  ), it seems the index filed is masked when it gets transfered. On the wire i see the index field is set to zero !!!  I tried installing the driver to the entire composite device too. still the behavior is same. Does anyone know how to use the index field with WinUsb_ControlTransfer function call?

TIA,

rk

 

Answer 1

rk77 wrote:

>

>I am using WinUSB to communicate with my device only through control

>endpoint.  When I use WinUsb_ControlTransfer to send setup packet

>( WINUSB_SETUP_PACKET Wsp = { 0x41, 0x60, 0x6, 0xFC, 0x4} ;  ),

>it seems the index filed is masked when it gets transfered.

>On the wire i see the index field is set to zero !!!

 

0x41 is a vendor request, output, aimed at an interface.  When the target

is an interface, the wIndex field must contain the target interface number.

0xFC is probably not a valid interface number.

 

If you want to use all three fields for arbitrary purposes, send your

request to the device (0x40) or to "other" (0x43).

--

Tim Roberts, [e-mail]

Providenza & Boekelheide, Inc.

 

---

Tim Roberts, DDK MVP Providenza & Boekelheide, Inc.