USB OTG
How to use the USB On The Go (OTG) port of the Armadeus boards under Linux.
Introduction
The USB OTG feature let you use the connector USB Mini-AB to connect at any time a device to your board or to connect your board to a host PC without enforcing any of these two modes.
Requirements
The USB OTG is available with the AFP28Dev board since the board revision 2 with the connector USB mini-AB. We have the plan to support this feature also on the AFP51Dev as soon as some project members can start this development.
Usage
In order to activate the OTG mode, no specific mode should not be enforced by the U-Boot otg_mode parameter:
BIOS> setenv extrabootargs BIOS> saveenv BIOS> boot
Your port is now ready to act as an USB OTG connector under linux. Once you have loaded your preferred gadget driver, you are ready to connect and use at any time an USB device or a host PC without rebooting the board to use the USB OTG feature.
- Please check the USB Gadget usage for a step by step procedure.
- How to use all the possible USB devices on your board can be found on the USB Host usage page
Known issues
You can use USB mini A male - USB A female adapter to connect regular USB peripherals to your board with the following limitation:
- Connect first the USB device to the adaptor before connecting them to the board.
- Disconnect first the adapter from the board instead of disconnecting the USB device from the adapter.
This is a limitation of current implementation on the 2.6.35 linux USB drivers
