I have an application where I need to have a PC talk to the TTL level serial port on a device (call it X) and also be able to have the PC send commands to a Panda (or something) that can trigger digital I/O ports on the device X as well. What I want is to connect a Panda to the serial port of X and connect a few other pins to digital I/O on X and then be able to see the serial port on the USB com port and be able to send commands to the Panda over USB.
Getting the serial port across is no problem - just read the serial port and write to usb; read the usb and write to the serial port. Just pass the data through. Open a com port on the PC to the CDC device on the Panda.
But for the command channel from the PC to the Panda, I could use some type of “escaped” commands in the serial data stream, or I could talk to a different CDC device on the Panda over the same USB connection. That would be my preference.
So, does the Panda or another FEZ have the ability to be more than one CDC com port at the same time. I bet it does Can some one point me at the APIs I will need? Thanks.
A bit more background: I have a bunch of devices (all the same in row on row of test benches) and I need to be able to talk to the serial port and use the digital I/O to hard reset or set configuration bits as if they were jumpers. My existing solution is a PIC based board with 2 serial ports - one is a pass-through that just does voltage level conversion to the device and the other is the command port for reset, etc. It is time for a new design that gets rid of the RS-232 ports. I want it to be freakin’ easy.