[WIP] USB Host support (working)

Search This thread

verygreen

Senior Member
Feb 13, 2011
1,305
2,637
TN
linuxhacker.ru
Hello!

I have been asked into looking for usb host support for nook touch. The hardware appears to be pretty similar to Nook Color, so there were no troubles in that area.


The kernel used by B&N for the Nook Touch is somewhat older than .32 kernel used for Nook Color, so the patch itself required some massage. Surprisingly B&N kernel already has usb host support compiled in, so you don't even need to change anything in kernel config, just apply the patch.

Just like in Nook Color, the id pin in the usb receptacle is not connected anywhere, so a special app is needed to switch the host mode on and off. The Nook Color usbhost switcher should work: https://github.com/verygreen/Nook-Color-usbhost-switcher though I cannot compile it for eclair, so I guess that needs some more massage and help here would be appreciated.

Meanwhile you can simply switch the mode from adb, type
Code:
echo host > /sys/devices/platform/musb_hdrc/mode
to enable usb host mode and type
Code:
echo peripheral > /sys/devices/platform/musb_hdrc/mode
to disable it.
The LED at the bottom that usually indicates charging status will light up in usb host mode even if the power is not connected.

The upside is you don't need a special OTG cable and can just use gender changer on your existing nook cable if you so desire.

Now, problems ;)
  • I have not tracked why yet, but self powered mode only works when you try to enable it first with external power plugged in first.
  • The user-friendly tool for usbhost mode switching needs to be compiled for eclair
  • The self-powered mode is very faint. Keeps up with my keyboard, but not even with a simple usb hub.
  • Battery drain is significant, though not sure what part of it is attributed to the usbhost mode and what to adb over wifi
  • Eclair init is buggy so input devices are unusable without a patch, see commit 6405c6953fa02d41d9f6377f4cdb947604f481c4 in google tree to sytem/core/init. I am attaching recompiled init binary that works.

Attachments: binary.zip contains:
  • uImage - prebuilt 1.1 kernel with the patch
  • uRamdisk - root ramdisk with fixed init, adb over wifi
  • init - just recompiled init binary for those who might need it
usbhost_patch.zip - just the patch itself in it's current form.

THANKS TO:
andrewed, who asked me to do this and also provided me with a device. He is on a quest to touchtype on e-paper with a USB physical keyboard, all described here: Project: E-Paper Tablet (typable!)
 

Attachments

  • binaries.zip
    2 MB · Views: 2,022
  • usbhost_patch.zip
    13.5 KB · Views: 2,085
Last edited:

verygreen

Senior Member
Feb 13, 2011
1,305
2,637
TN
linuxhacker.ru
That is awesome! How about audio and serial ports?

Thanks!
Audio will most probably require external power source. Also to make audio work there would need to be some changes to the libaudio, likely similar in nature to stuff I did for Nook Color, only for this older release of Android.

Serial ports will likely work as is as I don't think they draw too much power. The kernel support for usbserial would need to be added of course.
 

Thiso

Senior Member
Mar 16, 2010
127
23
Possibility for Bluetooth dongle? And thus audio?

Sent from my GT-I8150 using xda premium
 

apeine

Senior Member
Mar 9, 2011
268
31
Sao Paulo
Verygreen,

As of now, what is the use? Can I put an external keyboard as it is? Does it need a driver (or something of the sort) for that? Can I put a usb stick? Audio and BT, as I can see, need an extra effort...
Anyway, thank you for your effort. I thought I'd never see something like that for the STR.
 

verygreen

Senior Member
Feb 13, 2011
1,305
2,637
TN
linuxhacker.ru
Verygreen,

As of now, what is the use? Can I put an external keyboard as it is? Does it need a driver (or something of the sort) for that? Can I put a usb stick? Audio and BT, as I can see, need an extra effort...
Anyway, thank you for your effort. I thought I'd never see something like that for the STR.

You can use keyboard and mouse as is with just the files posted, no extra drivers need. Everything else would need more work at the android side.
 

cceerrtt

Senior Member
Sep 14, 2010
147
24
for some phones it is possible to buy usb to audio jack converter, e.g.
http://www.amazon.com/Headphones-Ea...6?s=electronics&ie=UTF8&qid=1327504575&sr=1-6
I don't know how much effort and changes is needed on kernel side to make it work though.

---------- Post added at 04:26 PM ---------- Previous post was at 04:21 PM ----------

Do I need to copy all three binaries? Also, could you prepare uRamdisk with adb over usb (not wifi) enabled? Thank you in advance.
 

dhkr234

Senior Member
Jan 27, 2011
570
158

verygreen

Senior Member
Feb 13, 2011
1,305
2,637
TN
linuxhacker.ru
Do I need to copy all three binaries? Also, could you prepare uRamdisk with adb over usb (not wifi) enabled? Thank you in advance.
You need the kernel uImage and uRamdisk files, init is already included.

As far as adb over usb is concerned, it's a bit pointless since there is only one usb receptacle, so you can either connect with adb over usb or connect some usb device, but not both at the same time.
That's why wifi makes more sense.
 

cceerrtt

Senior Member
Sep 14, 2010
147
24
You need the kernel uImage and uRamdisk files, init is already included.

As far as adb over usb is concerned, it's a bit pointless since there is only one usb receptacle, so you can either connect with adb over usb or connect some usb device, but not both at the same time.
That's why wifi makes more sense.

My point is that you don't need wireless access point with adb over usb. It is also more secure than adb over wifi with lower power consumption. Whenewer I need adb over wifi, I can enable it using one adb command. Moreover, using both adb and keyboard attached to nook would not be very frequent scenario (at least in my case).
 
Last edited:

Thiso

Senior Member
Mar 16, 2010
127
23
Let's hope so. But I have good hopes as BT intention is to be low power communication. In the post I was referring to earlier, the power communication of BT in use was similar to USB mouse in use...

Sent from my GT-I8150 using xda premium
 

Torimu.Joji

Senior Member
Jan 5, 2012
61
16
Brr...
www.nookroot.tk
TorimuNooter

I'll try to get this included in my TorimuNooter root! Maybe version 0.5 I'm working on 0.4 right now and I can't include your USB host support because it's not yet complete, but I will try to implement it as soon as I can.
Good work! :):)
 
  • Like
Reactions: andrewed

Renate

Recognized Contributor / Inactive Recognized Dev
@Googie2149: Any standard USB cable will work as well as any other.
The ID pin on the micro USB connector on the Nook is not going anywhere so a special OTG cable is not required.

I loaded in the new uImage and uRamdisk and things act more consistently, but I still can't get a keyboard to work.

Neither of the two utilities out there seem to work correctly for me. I do have su installed. I have had more success with simple commands

Code:
echo host > /sys/devices/platform/musb_hdrc/mode
echo peripheral > /sys/devices/platform/musb_hdrc/mode
cat /sys/devices/platform/musb_hdrc/mode

One thing is clear; the Nook adheres to the USB standard for supplying power, that is, it supplies it for 100 millisecs and if the peripheral signals back correctly it continues to supply it. Issuing a host command cause the red LED to flash for about a 1/10 of a second. Supplying power on the red wire is not necessary for host communication.

My setup has a powered hub and a cable with the red lead not carried through. I can issue a host command but it never seems to communicate. The status reads back "a_wait_vrise".

Does anybody have any insight into the FSM to say what is going on?
 

Top Liked Posts

  • There are no posts matching your filters.
  • 18
    Hello!

    I have been asked into looking for usb host support for nook touch. The hardware appears to be pretty similar to Nook Color, so there were no troubles in that area.


    The kernel used by B&N for the Nook Touch is somewhat older than .32 kernel used for Nook Color, so the patch itself required some massage. Surprisingly B&N kernel already has usb host support compiled in, so you don't even need to change anything in kernel config, just apply the patch.

    Just like in Nook Color, the id pin in the usb receptacle is not connected anywhere, so a special app is needed to switch the host mode on and off. The Nook Color usbhost switcher should work: https://github.com/verygreen/Nook-Color-usbhost-switcher though I cannot compile it for eclair, so I guess that needs some more massage and help here would be appreciated.

    Meanwhile you can simply switch the mode from adb, type
    Code:
    echo host > /sys/devices/platform/musb_hdrc/mode
    to enable usb host mode and type
    Code:
    echo peripheral > /sys/devices/platform/musb_hdrc/mode
    to disable it.
    The LED at the bottom that usually indicates charging status will light up in usb host mode even if the power is not connected.

    The upside is you don't need a special OTG cable and can just use gender changer on your existing nook cable if you so desire.

    Now, problems ;)
    • I have not tracked why yet, but self powered mode only works when you try to enable it first with external power plugged in first.
    • The user-friendly tool for usbhost mode switching needs to be compiled for eclair
    • The self-powered mode is very faint. Keeps up with my keyboard, but not even with a simple usb hub.
    • Battery drain is significant, though not sure what part of it is attributed to the usbhost mode and what to adb over wifi
    • Eclair init is buggy so input devices are unusable without a patch, see commit 6405c6953fa02d41d9f6377f4cdb947604f481c4 in google tree to sytem/core/init. I am attaching recompiled init binary that works.

    Attachments: binary.zip contains:
    • uImage - prebuilt 1.1 kernel with the patch
    • uRamdisk - root ramdisk with fixed init, adb over wifi
    • init - just recompiled init binary for those who might need it
    usbhost_patch.zip - just the patch itself in it's current form.

    THANKS TO:
    andrewed, who asked me to do this and also provided me with a device. He is on a quest to touchtype on e-paper with a USB physical keyboard, all described here: Project: E-Paper Tablet (typable!)
    7
    This is chinese for me again, sorry...

    Ni hao ma?

    Ok, no problem.

    Here is the official (interim, hacked) way to get your Nook to be an MP3 player.

    1. Root
    2. Install mali100's uImage with USB host mode and audio drivers
    3. Install superuser.apk and su
    4. Install UsbMode-1.4.apk (see below)
    5. Install AudioCtl-1.0.apk (see below)
    6. Create the text file /system/etc/asound.conf as shown here
    7. Plug in USB audio adapter through a special OTG cable adapter
    8. Using UsbMode, set in host mode
    9. Run AudioCtl, it should make beeping noises
    10. Go to your file manager and select a suitable song to play
    11. Goto step #10

    AudioCtl is very much a version 1.0
    It is necessary to use now as a workaround due to problems with mediaserver.
    You only need to run it once after each time of turning on the USB audio adapter.
    In the future, AudioCtl will have useful features.

    Note: Ignore all that stuff about ps, kill, mediaserver, etc. AudioCtl obviates all that.
    5
    USB Host Mode Swicth for Nook Simple Touch

    Attached is a Nook Simple Touch version of verygreens USB Host Mode switching app.

    Requires properly installed "su" in /system/bin

    Let me know if there are problems.
    5
    Ok, here's a summary.
    Depending on what you want to do not all of this may be required.

    For basic playback
    For basic recording or Skype
    • Modify /system/lib/hw/libaudio.so
      Code:
      [00009188] B1 F5 FA 54 => 70 BD 00 BF
      [000091EC] 6C 33 => 00 05
    • Patch /system/framework/framework.jar with AudioRecord.smali using mergesmali, in signature, in Nook121patch
    For recording directly through ALSA
    • Recorder.apk, in signature
    • Modify /system/etc/permissions
      Code:
         <permission name="android.permission.WRITE_EXTERNAL_STORAGE" >
             <group gid="sdcard_rw" />
             [b]<group gid="audio" />[/b]
         </permission>
    Jeez, it seems like a lot.
    4
    Is it possible to change the keyboard layout?

    Of course.

    There are two levels of processing turning a key press into a character.
    The first is mapping of the scan code into a key code.
    The second is mapping the key code and meta keys (shift, alt, etc) into a character.

    The first mapping is done using files like /system/usr/keylayout/qwerty.kl
    The second mapping is done using files like /system/usr/keychars/qwerty.kcm.bin
    The first file is conveniently in plain text, the second is a simple binary file.

    If you are simply swapping keys around you only need to change the .kl file
    If you want to make it so that shift 4 is Euro instead of dollar you need to change the kcm.bin file.

    You can just edit the .kl file. Before:
    Code:
      key  21  Y
    After:
    Code:
      key  21  Z
    This would make the key layout more "German-like" by making the center key in the top alpha row be considered the 'Z' key.

    The .kcm.bin are compiled files from source.
    I haven't looked into where the compiler comes from, I just modify the stock kcm.bin by hand.

    The file is broken down into 16 byte chunks with a 16 byte header.
    Here is the chunk for C (on my modified version):
    Code:
    000100 1F 00 00 00 43 00 32 00 63 00 43 00 E7 00 C7 00
    This means:
    • This chunk is about KEYCODE_C (0x1f) (uses Android key codes)
    • The visual for this key is 'C' (0x0043)
    • On a numeric keypad this would dial a 2 (0x0032) as in ABC on a phone
    • The unshifted UTF-16 value is 'c' (0x0063)
    • The shifted UTF-16 value is 'C' (0x0043)
    • The alt modified UTF-16 value 'ç' (0x00e7)
    • The alt-shift modified UTF-16 value is 'Ç' (0x00c7)

    You can also use alt combos for combining diacritics:
    • 0x0300 grave accent
    • 0x0301 acute accent
    • 0x0302 circumflex accent
    • 0x0303 tilde accent
    • 0x0308 umlaut accent

    To replace these files on your Nook, you will need to remount your system as R/W:
    Code:
    mount -o rw,remount /dev/block/mmcblk0p5 /system

    You can get fancier if you want to have some USB keyboards US and some Belgian.

    I await my shipment of Belgian chocolates. :D