UsbStartCtrlTransfer

Starts asynchronous Control Transfer with a specific endpoint.


 * Warning: Only one UsbStartCtrlTransfer may be outstanding to a particular endpoint.

Syntax
ulrc = UsbStartCtrlTransfer(Handle,ucEndpoint,ucAltSetting,ucRequestType,                            ucRequest,usValue,usIndex,pucParm,pucData,ulEvent)

Parameters

 * Handle : the Device Handle received from the previous UsbOpen.
 * ucEndpoint : the Endpoint Number appropriate for the control transfer.
 * ucAltSetting : the Alternate Setting of the interface having this endpoint.
 * ucRequestType : the characteristics of the Standard Device Request.
 * ucRequest : the specific request code of the Standard Device Request.
 * usValue : the request dependent value of the Standard Device Request.
 * usIndex : the request dependent index of the Standard Device Request.
 * ulEvent : the handle of the event semaphore to be posted on completion.
 * pucParm : the address of the buffer with variables usDatalength and usStatus.
 * usDataLength : the variable to specify/receive the number of data bytes.
 * usStatus : the variable to receive the asynchronous Completion Status.

For device-to-host data transfer:


 * pucData : the address of the buffer to receive the data bytes transferred.

For host-to-device data transfer:


 * pucData : the address of the buffer with the data bytes to be transferred.

Return Code
0x0000 - NO_ERROR

Errors
0x0057 - ERROR_INVALID_PARAMETER 0x1B58 - USB_NOT_INIT 0xFF0D - ERROR_INVALID_DATA 0xFF13 - ERROR_I24_INVALID_PARAMETER 0xFF13 - USB_IDC_PARMERR 0xFF18 - USB_IDC_ADDRINV 0xFF37 - ERROR_DEV_NOT_EXIST 0xFF5D - EROR_NO_ITEMS 0xFFA7 - ERROR_LOCK_FAILED

Status Code
0x0000 - USB_IORB_DONE

Errors
0x4000 - USB_IORB_REQUEST 0x80XX - USB_IORB_FAILED

Remarks

 * Warning:Only one UsbStartCtrlTransfer may be outstanding to a particular endpoint.

Example Code
//Code Snippet - UsbStartCtrlTransfer { APIRET ulrc; PUCHAR pucData; UCHAR ucAltSetting = 0; UCHAR ucEndpoint = 0; UCHAR ucData[4096]; UCHAR ucRequestType; UCHAR ucRequest; ULONG ulPostCount; ULONG ulTimeout = 8000; USHORT usIndex; USHORT usLength; USHORT usValue;

HEV hCtrlComplete; PHEV phCtrlComplete; PUSBCALLS_CTRL_RSP pCtrlResponse; USBCALLS_CTRL_RSP CtrlResponse;

//acquire semaphore phCtrlComplete = &hCtrlComplete; ulrc = DosCreateEventSem(NULL,phCtrlComplete,DC_SEM_SHARED,FALSE); printf("\nDosCreateEventSem - ulrc: 0x%04X (%hu)",ulrc,ulrc);

//start asynchronous control transfer ucRequestType = 0xA1; ucRequest = 0x01; //get interface class report usIndex = 0x0000; usValue = 0x0200; usLength = 8; //hid output report CtrlResponse.usDataLength = usLength; pCtrlResponse = &CtrlResponse; pucData = &ucData[0]; ulrc=UsbStartCtrlTransfer(Handle,ucEndpoint,ucAltSetting,ucRequestType,ucRequest,usValue,                           usIndex,(PUCHAR)pCtrlResponse,pucData,hCtrlComplete); printf("\nUsbStartCtrlTransfer - ulrc: 0x%04X (%hu)",ulrc,ulrc);

//await asynchronous control transfer complete ulrc = DosWaitEventSem(hCtrlComplete,ulTimeout); printf("\nDosWaitEventSem - ulrc: 0x%04X (%hu)",ulrc,ulrc); if (!ulrc) //success {   ulrc = CtrlResponse.usStatus; printf("\nCompletion Status - ulrc: 0x%04X (%hu)",ulrc,ulrc); usLength = CtrlResponse.usDataLength; if (!ulrc) //success {     int i; printf(" - hid input report:\n"); for (i=0;i<usLength;i++) printf("%02X",ucData[i]); } }  else {   // failure awaiting control transfer completion UsbCancelTransfer(Handle,ucEndpoint,ucAltSetting,hCtrlComplete); }

ulrc = DosResetEventSem(hCtrlComplete,&ulPostCount); printf("\nDosResetEventSem - ulrc: 0x%04X (%hu)",ulrc,ulrc);

//start asynchronous control transfer ucRequestType = 0x21; ucRequest = 0x09; //set interface class report usIndex = 0x0000; usValue = 0x0200; usLength = 8; //hid output report CtrlResponse.usDataLength = usLength; pCtrlResponse = &CtrlResponse; pucData = &ucData[0]; ulrc=UsbStartCtrlTransfer(Handle,ucEndpoint,ucAltSetting,ucRequestType,ucRequest,                           usValue,usIndex,(PUCHAR)pCtrlResponse,pucData,hCtrlComplete); printf("\nUsbStartCtrlTransfer - ulrc: 0x%04X (%hu)",ulrc,ulrc);

//await asynchronous control transfer complete ulrc = DosWaitEventSem(hCtrlComplete,ulTimeout); printf("\nDosWaitEventSem - ulrc: 0x%04X (%hu)",ulrc,ulrc); if (!ulrc) //success {   ulrc = CtrlResponse.usStatus; printf("\nCompletion Status - ulrc: 0x%04X (%hu)",ulrc,ulrc); usLength = CtrlResponse.usDataLength; if (!ulrc) //success {     int i; printf(" - hid output report:\n"); for (i=0;i<usLength;i++) printf("%02X",ucData[i]); } }  else {   // failure awaiting control transfer completion UsbCancelTransfer(Handle,ucEndpoint,ucAltSetting,hCtrlComplete); }

//release semaphore ulrc = DosCloseEventSem(hCtrlComplete); printf("\nDosCloseEventSem - ulrc: 0x%04X (%hu)",ulrc,ulrc); }

Related Functions

 * UsbCancelTransfer
 * UsbCtrlTransfer
 * UsbOpen