Lucent Technologies USS-720 manual Ioctlsetaltsetting, 4 I/O Control Codes continued, February

Preliminary User Guide, Rev. 2	USS-720
February 1999	USB Device Driver

4 I/O Control Codes (continued)

4.20 IOCTL_SET_ALTSETTING

IOCTL_SET_ALTSETTING sets the alternate interface setting. Details regarding parameters and error codes follow.

4.20.1 Parameters

lpInBuffer—Points to an buffer that contains a single byte that specifies one of the following values:

Value	Description
ALT_INTERFACE_0	Bulk Out pipe only.
ALT_INTERFACE_1	Bulk Out and Bulk In pipe.
ALT_INTERFACE_2	Bulk Out, Bulk In, Interrupt pipe, and 1284 register capabilities.

nInBufferSize—Specifies the size (in bytes) of the buffer pointed to by lpInBuffer. For this operation, this value should be 1.

lpOutBuffer—Points to an output buffer. Not used with this operation. Set to NULL.

nOutBufferSize—Specifies the size (in bytes) of the buffer pointed to by lpOutBuffer. Not used with this operation. Set to zero.

lpBytesReturned—Points to a DWORD that receives the actual size (in bytes) of the data stored into lpOutBuffer. Not used with this operation.

4.20.2 Notes

None.

4.20.3 Error Codes

ERROR_INVALID_ALTERNATESETTING—The alternate interface setting passed in for this command is invalid.

ERROR_INVALID_DESCRIPTOR—Configuration descriptor is invalid and could not set the alternate interface.

Lucent Technologies Inc. 7-29