How do You Keep the FX2 from Going Into Suspend State When It is Removed From the Board?

Question: How to you keep the EZ-USB device from going into the suspend state when it is self powered and removed from the bus?

 

Answer:

There are two pins on FX2LP for controlling the wakeup mode of the FX2. They also control whether the FX2 goes into the suspend mode. The two pins are WAKEUP and WU2 (an alternate pin) and whichever one is used must be tied active. The pin's polarity is programmable so firmware determines if it is high or low.

First consider how you want to configure the hardware and then control the WUPOL or WU2POL bits to match the pin and configure it as active. Example: tie the WAKEUP pin low and then program the WUPOL bit to zero.