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_CTRL_RSP pDataResponse;
USBCALLS_CTRL_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);
}