USB

[Felix]

Looking at

 

http://papilio.cc/uploads/Papilio/duousb-schematic.png

 

i am guessing it is not possible to be able to talk to the board

so as to be able to send raw data (like the cassette reader mentioned 2 yrs back for the ppro)

 

that is to say,

i currently have a project which runs on a PIC18F4550 (native usb) and a UI which sends the commands

to the PIC which makes the PIC do stuff and the UI displays the output / parses the PIC reply into something

useful.

 

i would get into the details of the PIC project but it would probably be boring for most of you

 

i wanted to start porting the functionality to an FPGA so as not to have to redesign / send out pcb files / get pcbs back / build the units.

 

thoughts?

[Jaxartes]

Not native USB, but a virtual serial port over USB.  Which is a bit more "old school" with the advantages and disadvantages that implies.  (Less plug-and-play, less possibilities for custom protocol, but easier to manage at both ends.)

 

I base what I'm saying on the Papilio Pro, but http://papilio.cc/index.php?n=Papilio.PapilioDUOHardwareGuide, seems to indicate the Duo will be similar: "Channel B is connected to the Papilio DUO in an Asynchronous serial UART configuration that is capable of speeds up to 3MHz".  I haven't used the Duo; I have a Papilio Pro which is similar but without the ATmega chip.

 

The USB connection to the Papilio would appear on the host computer as a serial port -- that is a COM port on Windows, a TTY on Linux.  Data rate is less than full USB, but may still be good enough, depending on how much data you want to pass.  Your protocol would require some changes to go over serial (which is just a stream of bytes each way) instead of USB (which has more control).

[Felix]

Thanks. Pretty much what I figured. Will have to do some math to see.

// F