Gadget Serial Driver on the USB device port

This article illustrate how to use the Linux Gadget Serial Driver to emulate an USB serial device accessible via a virtual serial port from your PC with an Acme Systems board.

To enable this feature is not requested any new driver on the factory default bootable microSD.

We'll illustrate how to communicate with an Acme board wired to your PC with a simple USB cable using Hyper Terminal or putty on Windows PC.

Download and save on your PC this file linux-cdc-acm.inf.

Plug a miniUSB cable between the FOX Board USB device port and a USB host port on your PC.

Type from the board command line:

modprobe g_serial

Windows should recognize the gadget serial device and ask for a driver. Tell Windows to find the driver in the folder that contains the linux-cdc-acm.inf file. For example, on Windows XP, when the gadget serial device is first plugged in, the "Found New Hardware Wizard" starts up. Select Install from a list or specific location (Advanced)", then on the next screen select "Include this location in the search" and enter the path or browse to the folder containing the "linux-cdc-acm.inf" file. Windows will complain that the Gadget Serial driver has not passed Windows Logo testing, but select "Continue anyway" and finish the driver installation.

On Windows XP, in the "Device Manager" (under "Control Panel", "System", "Hardware") expand the "Ports (COM & LPT)" entry and you should see "Gadget Serial" listed as the driver for one of the COM ports.

Use Hyper Terminal or Putty to open this serial port.

On the FOX side you can open /dev/ttyGS0 for example using minicom -s to send chars.

Related links

Sergio Tanzilli
Systems designer, webmaster of and founder of Acme Systems srl

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