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if disconnect usb cable and then reconnect or power it up by dc volt, doesn't it work?
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According to the DE0-nano page, it contains an "Altera serial configuration device – EPCS16". You can use this device to program the FPGA at power-on, i.e., when you insert it into a PC, or into a USB wall-charger (which saves you having to leave your PC on).
So get your design working, and then program the FPGA image onto the EPCS16. The design can contain a NIOS processor, and its code can also boot from this non-volatile memory.
Cheers,
Dave
Honored Contributor
