USB_TO_SERIAL.asm in USB to Serial firmware

Question: In the USB_TO_SERIAL.asm, 10h value is written to F2h. What is this F2h register?

 

Answer:

The CY64x13 hardware automatically generates SE0s. This feature was implemented specifically as a means of preventing babble in hub applications. For the most part, this behavior has been successfully implemented with no ill effects. However, in some host environments and in non-hub applications this might cause some problems. The register located at F2h is an undocumented register. Writing a 10h to register F2h disables the generation of SE0s.