Objective Development Forums

Hi

I want to make a small device which just present itself to my PC as a generic serial port device like /dev/ttyUSB0 so I do not have to have a special driver on my PC. I expect the communication to look like:


The project is very similar to this EasyLogger which interfaces to the keyboard. A good concept unless you need to have 2 or more devices connected.
http://www.obdev.at/products/vusb/easylogger.html

So I looked for a small and simple USB-serial driver at my system:


In the source it looks like it almost de nothing at all. It simply just use the generic serial device code with no hooks:
http://lxr.linux.no/#linux+v3.2/drivers ... rial/zio.c
It is a bit similar to a generic keyboard but for a serial port.

I know I am not supposed to present my device as another vendor:product but it looks like that if choose to use USB_DEVICE(0x1CBE, 0x0103) my system will automatically load the zio driver and I got a /dev/ttyUSB0 .

Will this work and is it possible to use V-USB for that?

Zilog has "drivers" for there device but they are just parameters for a default usb-serial:
http://www.zilogic.com/releases/zio-sw-1.1/drivers/
(it is just text files)

/hans

(I'm sorry if this question has been asked before. I could not find the answer)

Using V-USB as serial driver will is problematic. Because the CDC profile is not allowed with low-speed (and V-USB is always low-speed). It is possible, but it requires some hacks on the computer side. Also new USB chips seem to refuse this in some cases, and Windows 7 has also made this harder. In my opinion, it's not worth the trouble.

If you want USB serial, use an AVR with USB build in. Like the ATMega8U2

Thanks Daid, ATMega8U2 is really a better solution for me. And proto type board is awailable like "USB Serial Light Adapter" and others.