I have built a simple MicroBlaze project in ISE/EDK 9.2.02i targetting the XEM3010.
I used the import peripheral wizard to make a simple no-busses, no-interrupts peripheral that: (i) sets i2c_sda and i2c_scl to ‘Z’ and hi_muxsel to ‘0’ and (ii) connects buttons and leds to a gpio. The project doesn’t touch the other hi_xxx pins.
I used a Platform Cable USB / JTAG to download it and it and ran OK.
Attempts to download using FrontPanel failed until I edited the etc/bitgen.ut to set the StartUpClock to CCLK. A lesson was learnt, there.
The problem is that once my code is loaded and the MicroBlaze is running, FrontPanel reports a USB connection failure when I attempt to download over the top of my bitstream. Also, if Frontpanel is re-started when my code is loaded, it crashes; generating a windows ‘Send Error Report’ dialog.
What could it be in my bitstream that is causing the USB link to fail?