UsbStartDataTransfer

Description
Starts asynchronous Bulk or Interrupt Transfer with a specific endpoint.

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

Syntax
ulrc = UsbStartDataTransfer(Handle,ucEndpoint,ucAltSetting,pucParm,pucData,ulEvent,usFlags)

Parameters

 * Handle : the Device Handle received from the previous UsbOpen.


 * ucEndpoint : the Endpoint Number appropriate for the data transfer.


 * ucAltSetting : the Alternate Setting of the interface having this endpoint.


 * ulEvent : the handle of the event semaphore to be posted on completion.


 * usFlags : use 1 to transfer all data or 0 to allow less transferred.


 * 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 UsbStartDataTransfer may be outstanding to a particular endpoint.

Example Code
//Code Snippet - UsbStartDataTransfer { APIRET ulrc; PUCHAR pucData; UCHAR ucAltSetting = 0; UCHAR ucData[4096]; UCHAR ucEndpoint; ULONG ulPostCount; ULONG ulTimeout = 8000; USHORT usLength = sizeof(ucData); USHORT usFlags;

HEV hDataComplete; PHEV phDataComplete; PUSBCALLS_DATA_RSP pDataResponse; USBCALLS_DATA_RSP DataResponse;

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

//start asynchronous data transfer DataResponse.usDataLength = usLength; pDataResponse = &DataResponse; pucData = &ucData[0]; ucEndpoint = 0x81; usFlags = 0; //device-to-host transfer ulrc=UsbStartDataTransfer(Handle,ucEndpoint,ucAltSetting,(PUCHAR)pDataResponse,pucData,hDataComplete,usFlags); printf("\nUsbStartDataTransfer - ulrc: 0x%04X (%hu)",ulrc,ulrc);

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

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

//start asynchronous data transfer DataResponse.usDataLength = usLength; pDataResponse = &DataResponse; pucData = &ucData[0]; ucEndpoint = 0x02; usFlags = USB_TRANSFER_FULL_SIZE; //host-to-device transfer ulrc=UsbStartDataTransfer(Handle,ucEndpoint,ucAltSetting,(PUCHAR)pDataResponse,pucData,hDataComplete,usFlags); printf("\nUsbStartDataTransfer - ulrc: 0x%04X (%hu)",ulrc,ulrc);

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

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

Related Functions

 * UsbCancelTransfer
 * UsbDataTransfer
 * UsbOpen