Difference between revisions of "USB OTG"

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== Introduction ==
 
== Introduction ==
  
The USB OTG feature let you use the connector USB Mini-AB to connect at any time a [[USB_Gadget |device]] to your board or to connect your board to a [[USB_Host |host PC]] without enforcing any of these two modes.
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The USB OTG feature allows you to use the USB Mini-AB connector of your APFDev board to connect at any time a USB device (by acting as a [[USB Host]]) or to connect your system to your Host PC and be seen as a [[USB_Gadget |USB device (gadget)]]. OTG is automatically doing the right mode selection depending on the cable you are connecting to the APFDev OTG connector.
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This of course require that the cable your are using is OTG compatible. Otherwise you may end up continuing to force the OTG connector mode manually.
  
 
== Requirements ==
 
== Requirements ==
  
The USB OTG is available with the [[AFP28Dev]] board since the board revision 2 with the connector USB mini-AB.
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The USB OTG is available on the:
We have the plan to support this feature also on the [[AFP51Dev]] as soon as some project members can start this development.  
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* [[APF28Dev]] board (since revision 2 of the board == with the USB mini-AB connector),
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* [[APF6Dev]]
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We also have plan to support this feature on the [[APF51Dev]], as soon as some project members can start this development.
  
 
== Usage ==
 
== Usage ==
  
In order to activate the OTG mode, no specific mode should not be enforced by the U-Boot otg_mode parameter:
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In order to activate the OTG mode, no specific mode should be enforced by the U-Boot ''otg_mode'' bootargs parameter:
 
<pre class="apf">
 
<pre class="apf">
 
  BIOS> setenv extrabootargs
 
  BIOS> setenv extrabootargs
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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.
 
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| USB Gadget usage]] for a step by step procedure.
 
* Please check the [[USB_Gadget#Usage| 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#Using_USB_device | USB Host usage page]]  
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* How to use all the possible USB devices on your board can be found on the [[USB_Host#Using_USB_device | USB Host usage page]]
  
 
== Known issues ==
 
== Known issues ==

Latest revision as of 13:29, 31 March 2017

How to use the USB On The Go (OTG) port of the Armadeus boards under Linux.

Introduction

The USB OTG feature allows you to use the USB Mini-AB connector of your APFDev board to connect at any time a USB device (by acting as a USB Host) or to connect your system to your Host PC and be seen as a USB device (gadget). OTG is automatically doing the right mode selection depending on the cable you are connecting to the APFDev OTG connector. This of course require that the cable your are using is OTG compatible. Otherwise you may end up continuing to force the OTG connector mode manually.

Requirements

The USB OTG is available on the:

  • APF28Dev board (since revision 2 of the board == with the USB mini-AB connector),
  • APF6Dev

We also have plan to support this feature on the APF51Dev, as soon as some project members can start this development.

Usage

In order to activate the OTG mode, no specific mode should be enforced by the U-Boot otg_mode bootargs 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.

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

Links