I am working with FX2LP and cyusb driver on Win7. I know that calls to CyApi from different thread within an application is a safe practice. Instead I am working with two separated application that are making calls to XferData to the same device on different endpoints at the same moment. Is it a safe practice?
This is a common practice, in fact in our USB-Serial devices ( USB to 2 Serial ports) this is very common. Since you are calling two different end points, it should not matter and there will not be any data integrity problems.