= libam7xxx

libam7xxx is an Open Source library to communicate via USB with projectors and
Digital Picture Frames based on the Actions Micro AM7XXX family if ICs.

libam7xxx makes it possible to use these devices as USB displays on
non-Windows Operating Systems like GNU/Linux or Android/Linux just to name
a few, and on non-PC platforms like for instance mobile phones, tablets or
game consoles.

The first driver supporting these devices was _acerc11xdrv_ from Reto Schneider:
https://github.com/rettichschnidi/acerc11xdrv

Another project with the same purpose is _acerc110_ from Thomas Baquet:
https://github.com/lordblackfox/acerc110

== AM7XXX

An overview of some AM7XXX chips (AM7211A AM7212 AM7212P AM7318 AM7213D
AM7213V) can be found in http://www.actions-micro.com/dpf_psg.pdf

An example of datasheet illustrating the functionalities of such ICs (AM7531)
is at: http://wenku.baidu.com/view/543c8b4d852458fb770b56ee.html

== Supported devices

The devices supported by libam7xxx use USB bulk transfers and a simple packet
based protocol to exchange data and commands to and from a host system and the
AM7XXX chip.

Devices based on Actions Micro/Action Media designs generally use the USB
VendorID +1de1+, and they can have two operational modes:

 - USB Mass Storage mode (e.g. ProductID: +1101+)
 - Generic bulk data transfer mode, or Display mode (e.g. ProductID: +c101+)

On recent GNU/Linux systems the switch from Mass Storage mode to Display mode
is performed automatically by
http://www.draisberghof.de/usb_modeswitch/[USB_ModeSwitch], or can be done
manually with the command:

 $ sudo usb_modeswitch \
   --default-vendor 0x1de1 \
   --default-product 0x1101 \
   --message-content 55534243087052890000000000000cff020000000000000000000000000000

Examples of devices based on AM7XXX are:

  - Acer Series C pico projectors (C20, C110, C112):
      * http://www.acer.it/ac/it/IT/content/models/projector-c
      * http://support.acer.com/product/default.aspx?modelId=3888
    
  - Philips/SagemCom PicoPix projectors (PPX 1020, PPX 1230, PPX 1430, PPX
    1630):
      * http://www.philips.co.uk/c/pocket-projector/179840/cat/
      * http://www.sagemcom.com/EN/products/image-sound/pico-video-projectors.html

  - CEL-TEC MP-01:
      * http://www.kabelmanie.cz/miniprojektor-cel-tec-mp-01/

  - Other unbranded projectors:
      * http://www.dealextreme.com/p/portable-home-office-mini-usb-2-0-lcos-projector-16-9-45019

  - HannSpree digital picture frames (but it has not been verified yet if
    those can be actually used as USB displays):
      * http://europe.hannspree.net/onweb.jsp?prod_no=3333333621&webno=3333333317
      * http://europe.hannspree.net/onweb.jsp?prod_no=33333337:4&webno=3333333317

Maybe other devices reported as supporting "Display over USB (DoUSB)" like
Acer K330 or some Optoma projectors could be used with this library, but
this needs still needs to be verified.