I have an XEM 3005 FPGA and am having troubles with the external power. It works fine when powered by the usb, but does not work when switched to external power. I do not believe it is an issue with volatile memory, because in both cases I am running it with the switch in the prom config mode. This has been confirmed by cutting the power to the board after programming, and then reconnecting it. When powered by the usb, it works fine. The external power source has trouble. The jumper is put in the +VCC mode, so that shouldn?t be the issue. The FPGA is mounted to a BRK 3005 breakout board to which the external power is connected. I have used a multimeter to check the labeled power circles on the FPGA board (the ones labeled 3.3V, 1.2V, GND) The 3.3V and 1.2V each measure correctly (relative to GND). The +5V/USB circle reads small or nonexistent voltages. I assumed this is because the usb is not connected (it IS labeled usb). It reads 5V when usb is connected.
Do you have any suggestions about how to fix this issue?