Description

This function open the connection to the selected by a number (starting from zero) Trenz Electronic USB FX2 device number  (Cypress driver derivative and VID = 0xbd0, PID=0x0300) connected to a host computer's USB port.

Description of internal procedure

This function takes an already initialized USB device list, searches for Trenz Electronic USB FX2 devices (Cypress driver derivative and VID = 0xbd0, PID=0x0300) connected to host computer's USB ports and counts them.
An internal operation that closes an handle to the CyUSB.sys driver (or a derivative like TE_USB_FX2_xx.sys) is executed instead (see page 33 of CyAPI.pdf).
If one or more devices are attached and

  • if 0 ≤ CardNumber ≤ (number of attached devices – 1), then the selected module is not directly given by USBDeviceList (CCyUSBDevice type). An internal operation that opens a handle to CyUSB.sys driver (or a derivative like TE driver) is executed instead (see page 45 of CyAPI.pdf). This handle is internally managed by CyAPI.lib, therefore there is no need to expose them to the user.
  • if CardNumber ≥ number of attached devices, thenUSBDeviceList (CyUSBDevice type) is not initialized to null (the device list is not erased). An internal operation that closes an handle to CyUSB.sys driver (or a derivative like TE driver) is executed instead (see page 33 of CyAPI.pdf).
A more intuitive name for this function would have been TE_USB_FX2_SelectCard().
You can use this function to select the desired module without the need to call TE_USB_FX2_Close() before. Though doing so would not cause any problems.
Close() is automatically carried out by the TE_USB_FX2_Open() function if a handle to the driver is already open (i.e. a TE_USB_FX2_Open() has been successfully called before).

If no device is attached, USBDeviceList is not initialized to null (the device list is not erased).

 

Use of the code

Declaration

TE_USB_FX2_CYAPI int TE_USB_FX2_Open(CCyUSBDevice *USBDeviceList, int CardNumber);

Function Call

Your application program shall call this function like this:

TE_USB_FX2_Open(USBDeviceList, CardNumber);

Parameters

CCyUSBDevice *USBDeviceList

CCyUSBDevice is a type defined in CyAPI.lib. Its name is misleading because it is not a class that represents a single USB device, but it rather represents a list of USB devices.
CCyUSBDevice is the list of devices served by the CyUSB.sys driver (or a derivative like TE_USB_FX2_xx.sys). This parameter is passed by pointer. See page 7 and pages 23-49 of CyAPI.pdf (Cypress CyAPI Programmer's Reference).

int CardNumber

This is the number of the selected Trenz Electronic USB FX2 device (module).

Return Value

int : integer type

This function returns true (ST_OK=0) if it is able to find the module selected by CardNumber. If unable to do so, it returns false (ST_ERROR=1).

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