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Description

Brief Description

This function instantiate the driver buffer (host computer buffer) for a single TE USB FX2 module write connection.

Longer Description

This function takes an already initialized USB device list (USBDevice previously selected by TE_USB_FX2_Open()) and a not initialized CCyBulkEndPoint double pointer, BulkOutEP. This function selects the endpoint to use: you shall choose EP8 (0x08) (endpoints EP4(0x04) or EP2(0x02) are also theoretically possible).

Description of internal procedure

TE_USB_FX2_SetData_InstanceDriverBuffer() function instantiates the class used by CyAPI to use Bulk EndPoint (CCyBulkEndPoint, see pages 9 to 11) and initializes the parameters of this class instantiation.

...

The last parameter force the instantiation of the driver buffer (SW side, on the host computer) for the endpoint 0x86; this buffer has a size in byte given by DeviceDriverBufferSize. This value is of great importance because the data throughput is strongly influenced by this parameter (see Data Transfer Throughput Optimization).

Use of the code

Declaration

TE_USB_FX2_CYAPI int TE_USB_FX2_SetData_InstanceDriverBuffer(CCyUSBDevice *USBDeviceList, CCyBulkEndPoint **BulkOutEP, PI_PipeNumber PipeNo,unsigned long Timeout, int BufferSize);

Function Call

Your application program shall call this function like this:

TE_USB_FX2_SetData_InstanceDriverBuffer (USBDeviceList, &BulkOutEP, PipeNo, Timeout, BufferSize);

Parameters

CCyUSBDevice *USBDeviceList

...

int BufferSize

Itis It is the dimension (in bytes) of the driver buffer (SW) used in data transmission of a single endpoints (EP8 0x08 in this case); the total buffer size is the sum of BufferSize of every endpoint used. BufferSize has a strong influence on DataThroughput. If BufferSize is too small, DataThroughput can be 1/3-1/2 of the maximum value (from a maximum value of 24 Mbyte/s for read transactions to an actual value of 18 Mbyte/s). See 6 TE_USB_FX2_CyAPI.dll: Data Transfer Throughput Optimization.

Return Value

int : integer type

This function returns true (ST_OK=0) if the selected BulkEndPoint exists in the firmware (it is able to instantiate the driver buffer). This function returns false (ST_ERROR=1) otherwise.

enum ST_Status
{
     ST_OK = 0,
     ST_ERROR = 1
}; 

Code example

int TX_PACKET_LEN = 51200;//102400; 
 int packetlen = TX_PACKET_LEN;
 unsigned int packets = 500;//1200;//1200;
 unsigned int DeviceDriverBufferSize = 131072;//409600;//131072102400;
 unsigned long TIMEOUT= 18200;
 byte * data;
 byte * data_temp = NULL;
 unsigned int total_cnt = 0;
 unsigned int errors = 0; 
 data = new byte [TX_PACKET_LEN*packets]; //allocate memory 
 PI_PipeNumber PipeNo = PI_EP8; 
 //test starts test
 SendFPGAcommand(USBDeviceList,FX22MB_REG0_START_RX); 
 CCyBulkEndPoint *BulkOutEP = NULL; 
 TE_USB_FX2_SetData_InstanceDriverBuffer (USBDeviceList, &BulkOutEP, PipeNo, TIMEOUT, DeviceDriverBufferSize); 
 ElapsedTime.Start(); //StopWatch start
 for (unsigned int i = 0; i < packets; i++)
 {
 	packetlen = TX_PACKET_LEN;
 	data_temp = &data[total_cnt];
 	//cout << "Address &BulkInEP" << &BulkInEP << endl;
 	//cout << "Address BulkInEP" << BulkInEP << endl;
 	//cout << "Address *BulkInEP" << (*BulkInEP) << endl;
 	if (TE_USB_FX2_SetData(&BulkOutEP, data_temp, packetlen)) 
 	{
 		cout << "ERROR read" << endl;
 		errors++;
 		break;
 	}
 	total_cnt += packetlen;
 }
 //DEBUGStopWatch timer StopWatchstops 
 TheElapsedTime = ElapsedTime.Stop(false); 
//test stops
SendFPGAcommand(USBDeviceList,FX22MB_REG0_STOP);