Stefan Reinauer wrote:
The only USB option is a Debug Class device.
Or the Artec LPC dongle -
Sorry, I meant for USB connection to system being debugged. :)
it can transport POST codes via usb-serial from the target... For someone with VHDL knowledge it might be possible to add a "fake serial port" to the dongle.
The way to get data out that I like the best is to use reads-mean-write, where a sequence of reading from certain addresses sends the lowest byte of the last read address via USB to the host and the user.
Unfortunately, the dongle is already a serial device so it is difficult to create another serial port. That would be done using a kernel line discipline.
Ideally, the USB descriptors and USB firmware in the dongle could be changed instead, which would allow for more channels besides the current communication.
But I don't think it's doable with the FTDI USB chips, they are much too simple.
It would of course be possible to use the existing USB-serial channel, just that the dongle would need to be reset before the next reprogram, once it has entered the reads-mean-write mode. That might be OK.
//Peter