finally I found some time to look into this problem, sorry for the late delay.
I tried your program and started it maybe 50 times without an issue. So I cannot reproduce your problem.
I know that if you do Ctrl-C then you might have some data "stuck" in the USB interface, like you ask for a
waveform data buffer but you never read it because you got interrupted by the Ctrl-C. But when you reinitialize
the board the next time, all stuck data is drained before the board is initialized. This is done in DRS.cpp
around line 343:
/* drain any data from Cy7C68013 FIFO if FPGA startup caused erratic write */
i = musb_read(usb_interface, 8, buffer, sizeof(buffer), 100);
if (i > 0)
printf("%d bytes stuck in buffer\n", i);
} while (i > 0);
So occasionally, after a restart after a Ctrl-C, you will see "xxx bytes stuck in buffer", but then the boards
should come up correctly.
If you have the problem without Ctrl-C, then maybe your specific board has a hardware problem? Do you have
access to another board?