Gumstix User Wiki - User contributions [en]

Category:How to - usb

2011-08-02T19:22:04Z

Gerardo Richarte: fixed links

Note: if you have issues with USB not resuming properly after a suspend on Overo, please see [http://old.nabble.com/Update-on-Overo-EHCI-issues-td27617583.html#a27617583 this] forum post.
==USBNet with Overo==

The OTG USB port on the Overo expansion boards support USB networking. To enable this, the OTG port needs to be configured as a USB peripheral or gadget. The default kernels from Gumstix have the OTG port configured to act as a USB host.

The procedure for changing the configuration requires rebuilding your kernel, so you should first be comfortable with [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Setting-up-a-build-environment/111.html setting up a build environment] and building images for your Overo.

The following steps assume you are using a recent snapshot of the gumstix-oe git tree and are going to use kernel version 2.6.31 or greater. Though this procedure currently does not work with 2.6.39, as there are some inconsistencies between linux-omap3_2.6.39.bb recipe and the configuration (.config/defconfig) file shipped by default. See note below for more info on 2.6.39.

The gumstix recipes for these kernels have a variable that allows you to specify how the OTG usb port is configured.

Gumstix Overos use the linux-omap3 kernels by default. You can check which kernel version you'll be working with this way:

$ cd ${OVEROTOP}
$ bitbake --show-versions | grep linux-omap3
linux-omap3 0:2.6.34-r81

So the recipe file in this case would be ${OVEROTOP}/org.openembedded.dev/recipes/linux/linux-omap3_2.6.34.bb.

You'll see a line in there

MUSB_MODE ?= "host"

There are three valid values for MUSB_MODE: "host", "peripheral" or "otg".

You could change the MUSB_MODE assignment directly in the recipe, but a better way to do this is to modify your local.conf file and add a MUSB_MODE variable.

The ?= assignment means "host" will be assigned to MUSB_MODE only if it does not already have a value which it will if you give it one in local.conf.

The local.conf file is found here ${OVEROTOP}/build/conf/local.conf.

Add the line

MUSB_MODE = "peripheral"

or

MUSB_MODE = "otg"

depending on your preference.

===Note on 2.6.39===

There is currently an inconsistency between the recipe linux-omap3_2.6.39.bb and the default configuration (.config/defconfig) shipped, see [http://old.nabble.com/linux-omap3-2.6.39-build-failure-in-overo-2011.03-branch-td32094095.html this post] and [http://old.nabble.com/Re%3A-Thumbo-in-Gadget-mode-and-USBNet-p32171580.html this other post]. The latter, together with [[Kernel_Reconfiguration]], is what worked for me.

==Rebuild your kernel==

$ cd ${OVEROTOP}
$ bitbake -c clean linux-omap3
$ bitbake linux-omap3

And then rebuild your rootfs since the drivers available in /lib/modules will have changed.

$ bitbake omap3-console-image

Change omap3-console-image to whatever image you use.

Install the new kernel and rootfs the way you normally would using either a
[http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Creating-a-bootable-microSD-card/111.html microSD card]
or by copying to [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Writing-images-to-onboard-nand/111.html onboard nand].

Once you have booted the new system, you still need to load the g_ether driver since it was built as a module.

You can add g_ether to /etc/modules if you always want it to load at boot.

root@overo# modbprobe g_ether
g_ether gadget: using random self ethernet address
g_ether gadget: using random host ethernet address
usb0: MAC d6:2c:8f:d9:51:32
usb0: HOST MAC f2:99:dc:4c:cb:7a
g_ether gadget: Ethernet Gadget, version: Memorial Day 2008
g_ether gadget: g_ether ready

root@overo:~# ifconfig -a
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

usb0 Link encap:Ethernet HWaddr D6:2C:8F:D9:51:32
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

Configure the usb0 interface the way you would any other.

For example

root@overo:~# ifconfig usb0 192.168.20.2 netmask 255.255.255.0

If you then plug the usb OTG cable into a host computer ready for usb networking you'll get a console message

g_ether gadget: high speed config #1: CDC Ethernet (ECM)

The rest is all standard Linux networking.

Category:How to - usb

2011-08-02T18:07:27Z

Gerardo Richarte: added infor on configuring 2.6.39

Note: if you have issues with USB not resuming properly after a suspend on Overo, please see [http://old.nabble.com/Update-on-Overo-EHCI-issues-td27617583.html#a27617583 this] forum post.
==USBNet with Overo==

The OTG USB port on the Overo expansion boards support USB networking. To enable this, the OTG port needs to be configured as a USB peripheral or gadget. The default kernels from Gumstix have the OTG port configured to act as a USB host.

The procedure for changing the configuration requires rebuilding your kernel, so you should first be comfortable with [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Setting-up-a-build-environment/111.html setting up a build environment] and building images for your Overo.

The following steps assume you are using a recent snapshot of the gumstix-oe git tree and are going to use kernel version 2.6.31 or greater. Though this procedure currently does not work with 2.6.39, as there are some inconsistencies between linux-omap3_2.6.39.bb recipe and the configuration (.config/defconfig) file shipped by default. See note below for more info on 2.6.39.

The gumstix recipes for these kernels have a variable that allows you to specify how the OTG usb port is configured.

Gumstix Overos use the linux-omap3 kernels by default. You can check which kernel version you'll be working with this way:

$ cd ${OVEROTOP}
$ bitbake --show-versions | grep linux-omap3
linux-omap3 0:2.6.34-r81

So the recipe file in this case would be ${OVEROTOP}/org.openembedded.dev/recipes/linux/linux-omap3_2.6.34.bb.

You'll see a line in there

MUSB_MODE ?= "host"

There are three valid values for MUSB_MODE: "host", "peripheral" or "otg".

You could change the MUSB_MODE assignment directly in the recipe, but a better way to do this is to modify your local.conf file and add a MUSB_MODE variable.

The ?= assignment means "host" will be assigned to MUSB_MODE only if it does not already have a value which it will if you give it one in local.conf.

The local.conf file is found here ${OVEROTOP}/build/conf/local.conf.

Add the line

MUSB_MODE = "peripheral"

or

MUSB_MODE = "otg"

depending on your preference.

===Note on 2.6.39===

There is currently an inconsistency between the recipe linux-omap3_2.6.39.bb and the default configuration (.config/defconfig) shipped, see [http://old.nabble.com/linux-omap3-2.6.39-build-failure-in-overo-2011.03-branch-td32094095.html|this post] and [http://old.nabble.com/Re%3A-Thumbo-in-Gadget-mode-and-USBNet-p32171580.html|this other post]. The latter, together with [[Kernel_Reconfiguration]], is what worked for me.

==Rebuild your kernel==

$ cd ${OVEROTOP}
$ bitbake -c clean linux-omap3
$ bitbake linux-omap3

And then rebuild your rootfs since the drivers available in /lib/modules will have changed.

$ bitbake omap3-console-image

Change omap3-console-image to whatever image you use.

Install the new kernel and rootfs the way you normally would using either a
[http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Creating-a-bootable-microSD-card/111.html microSD card]
or by copying to [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Writing-images-to-onboard-nand/111.html onboard nand].

Once you have booted the new system, you still need to load the g_ether driver since it was built as a module.

You can add g_ether to /etc/modules if you always want it to load at boot.

root@overo# modbprobe g_ether
g_ether gadget: using random self ethernet address
g_ether gadget: using random host ethernet address
usb0: MAC d6:2c:8f:d9:51:32
usb0: HOST MAC f2:99:dc:4c:cb:7a
g_ether gadget: Ethernet Gadget, version: Memorial Day 2008
g_ether gadget: g_ether ready

root@overo:~# ifconfig -a
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

usb0 Link encap:Ethernet HWaddr D6:2C:8F:D9:51:32
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

Configure the usb0 interface the way you would any other.

For example

root@overo:~# ifconfig usb0 192.168.20.2 netmask 255.255.255.0

If you then plug the usb OTG cable into a host computer ready for usb networking you'll get a console message

g_ether gadget: high speed config #1: CDC Ethernet (ECM)

The rest is all standard Linux networking.

Kernel Reconfiguration

2011-08-02T18:06:57Z

Gerardo Richarte: added info on configuring 2.6.39

[[Category:How_to_-_linux]]
[[Category:How_to_-_general]]
There are several possible work flows for modifying the kernel:
[[http://blogs.elphel.com/2009/12/openembeddedangstrom-kernel-workflow/ Using bitbake]]
[[http://bec-systems.com/site/521/best-practices-for-kernel-development-with-openembedded Using kernel tools]]

==Overo==

These instructions assume you are using the default gumstix-oe kernel which is declared here

$ cd $OVEROTOP
$ grep linux org.openembedded/conf/machine/overo.conf
PREFERRED_PROVIDER_virtual/kernel = "linux-omap3"

And the current revision as defined here

$ bitbake --show-versions | grep linux-omap3
linux-omap3 0:2.6.32-r51

So the rest of the example will assume linux-omap3-2.6.32 revision 51. This is the kernel that will be built when we use the reference 'virtual/kernel' in bitbake commands.

Substitute the kernel version and revision your system is using in the following steps.

First build the kernel normally with bitbake. If you have built an image, then it's already done.

If not run this command

$ bitbake virtual/kernel

This will create a source directory in the ${OVEROTOP}/tmp/work/overo-angstrom-linux-gnueabi directory.
In this case it will be

${OVEROTOP}/tmp/work/overo-angstrom-linux-gnueabi/linux-omap3-2.6.32-r51

To modify the kernel configuration, run menuconfig via bitbake. Make your changes and save the configuration.

$ bitbake -c menuconfig virtual/kernel

The new kernel configuration file you created can be found here.

${OVEROTOP}/tmp/work/overo-angstrom-linux-gnueabi/linux-omap3-2.6.32-r51/git/.config

Copy that file to where the bitbake recipe for the kernel will use it.

$ cp ${OVEROTOP}/tmp/work/overo-angstrom-linux/gnueabi/linux-omap3-2.6.32-r51/git/.config \
${OVEROTOP}/org.openembedded.dev/recipes/linux/linux-omap3-2.6.32/overo/defconfig

For 2.6.39 I used:

$ cp ${OVEROTOP}/tmp/work/overo-angstrom-linux-gnueabi/linux-omap3-2.6.39-r101/git/.config \
${OVEROTOP}/org.openembedded.dev/recipes/linux/linux-omap3/overo/defconfig

Then rebuild the kernel.

$ bitbake -c clean virtual/kernel
$ bitbake virtual/kernel

Then rebuild the rootfs to get the modules installed correctly.

Substitute the image you are using, the example if you are using the omap3-console-image.

$ bitbake omap3-console-image

Finally, install the new kernel and rootfs the way you normally would using either a
[http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Creating-a-bootable-microSD-card/111.html microSD card]
or by copying to [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Writing-images-to-onboard-nand/111.html onboard nand].

==Verdex==

To reconfigure the kernel with the current state of Gumstix's OE things, you will need ''gnome-terminal''. Run this command: '''bitbake gumstix-kernel -c menuconfig'''

NOTE: You have to have ncurses and ncurses-dev installed in order for the MENUCONFIG to actually work. 
NOTE: If a screen flashes infront of you and dissapears edit $OE_HOME/org.openembedded.snapshot/conf/bitbake.conf to the following 
<code><pre>
-GNOME_TERMCMDRUN = '${GNOME_TERMCMD} -x ${SHELLRCCMD}'
+GNOME_TERMCMDRUN = '${GNOME_TERMCMD} -x ${SHELLCMDS}'
</pre></code>

NOTE: If you don't have gnome-terminal installed and wish to use xterm instead, use:
<code><pre>
-GNOME_TERMCMD = 'gnome-terminal --disable-factory -t "$TERMWINDOWTITLE"'
-GNOME_TERMCMDRUN = '${GNOME_TERMCMD} -x ${SHELLRCCMD}'
+GNOME_TERMCMD = 'xterm -title "$TERMWINDOWTITLE"'
+GNOME_TERMCMDRUN = '${GNOME_TERMCMD} -e ${SHELLCMDS}'
</pre></code>

The kernel config information is kept in 
''$OE_HOME/com.gumstix.collection/packages/linux/gumstix-kernel-2.6.XX/gumstix-custom-YYYYY/defconfig'' 
where XX is the current default kernel version for your bitbake environment. That nugget is set in the
''$OE_HOME/com.gumstix.collection/conf/machine/include/gumstix.inc'' file, under the PREFERRED_VERSION_gumstix-kernel
and YYYYY is usually one of connex/basix/verdex. That nugget comes from 
''$OE_HOME/build/conf/auto.conf''

After running menuconfig, running "bitbake -c rebuild gumstix-kernel" will blow away the customizations just made. There is probably a better way to do this, but in order to preserve the customizations, you can copy the new config file and replace the default config. For example, to preserve a verdex board's config, do:

<code><pre>
cp \
$OE_HOME/tmp/work/gumstix-custom-verdex-angstrom-linux-gnueabi/gumstix-kernel-2.6.21-r1/linux-2.6.21/.config \
$OE_HOME/com.gumstix.collection/packages/linux/gumstix-kernel-2.6.21/gumstix-custom-verdex/defconfig
</pre></code>

Now that you have replaced the default config, the following commands will rebuild and repackage the new kernel and create new images for you:

<code><pre>
bitbake -c rebuild gumstix-kernel
bitbake -c rebuild task-base-gumstix
bitbake gumstix-basic-image
</pre></code>

==Other notes==
Totally lost inside of menuconfig? Press '/' to search for appropriate options.

Want to know more about the kernel? I found the 'Linux Kernel in a Nutshell' book (not to be confused with the 'Linux in a Nutshell' book) quite helpful. The book is freely available online here (http://www.kroah.com/lkn/); Chapter 4 (Configuring and Building) and Chapter 6 (Upgrading a Kernel) as well as the first bit of Chapter 7 (Customizing a Kernel) and the last bit of Chapter 8 (Kernel Configuration: Kernel Debugging) have useful notes about kernel configuration.

Your kernel is now larger than the 1MB originally specified so do_sizecheck() fails?
You'll probably want to edit the ~/verdex-oe/org.openembedded.dev/conf/machine/include and change the maximum image size to, say, 2MB, i.e. KERNEL_IMAGE_MAXSIZE = "2097153". Actually, you should really do this in the user.collections directory to keep the original source tree clean.

User:Gerardo Richarte

2011-07-07T20:47:35Z

Gerardo Richarte:

7-July-2011 - I'm starting to develop on the Gumstix platform and I expect to do it for some time, I already have my Caspa working and I have already built a custom kernel and filesystem.

I'm an experienced software developer (24+ years of programming) , both in low and high level (down from assembly up to Smalltalk). I also have formal studies in electronics and maths.

Caspa camera boards

2011-07-07T20:44:09Z

Gerardo Richarte: How to save a single picture into a file

The Caspa series of Camera Boards from Gumstix

The MT9V032 sensor, at the heart of the Caspa FS camera board and the Caspa VL camera board, is not yet supported in the kernel, so a little work is necessary to get the camera up and running.

OMAP35x processors have dedicated hardware for capturing and processing data from image sensors. The Caspa camera sensor outputs raw 10-bit Bayer images which is transferred to the Image Signal Processor (ISP) via a parallel interface. The ISP contains various sub-modules that can be exported as Video for Linux (V4L2) devices in /dev. For additional hardware information see the external links section.

[[Image:Altoids.jpg|thumb|300px]]

== Quickstart ==

=== Hardware ===

[[Image:CaspaHardware.jpg|thumb|300px]]

Insert the white ribbon cable contact-side-up into the Caspa connector and contact side down into the Overo connector.

Using a small flat-head screwdriver, loosen the lensholder set screw and rotate the lens to adjust the focus.

=== Install Pre-built Kernel ===

The easiest way to get started is to replace the kernel and modules of an existing image. This has been tested on an Overo Fire with a Tobi expansion board using the desktop image available [http://www.sakoman.com/feeds/omap3/glibc/images/overo/201011150741/ here].

Get the kernel and modules.
$ wget http://cumulus.gumstix.org/images/angstrom/misc/caspapx/uImage-2.6.34
$ wget http://cumulus.gumstix.org/images/angstrom/misc/caspapx/modules-2.6.34.tgz

Copy to a bootable microSD card.
$ tar -xf modules-2.6.34.tgz -C /media/mmcblk0p2/
$ cp uImage-2.6.34 /media/mmcblk0p1/uImage
$ cp uImage-2.6.34 /media/mmcblk0p2/boot/uImage

Alternatively, if you have a network connection, you can copy the files without removing the microSD.
$ tar -xf modules-2.6.34.tgz
$ scp -r lib root@overo:/
$ scp uImage-2.6.34 root@overo:/boot/uImage
$ scp uImage-2.6.34 root@overo:/media/mmcblk0p1/uImage
$ ssh root@overo 'depmod; shutdown -r now'

=== Test ===

From the serial console:

# export DISPLAY=:0.0

# gst-launch v4l2src ! xvimagesink
''or''
# mplayer tv:// -tv driver=v4l2:device=/dev/video0

If you just want to take a picture:

# mplayer tv:// -vo png -ss 1 -frames 1 -loop 1 -tv driver=v4l2:device=/dev/video0

From the desktop:

<left-click> Applications > Multimedia > Cheese

If video0 doesn't appear in /dev you might have to load the driver manually.

# depmod
# modprobe mt9v032

== Bitbake ==

You can build the kernel and modules using bit-bake. This allows you to incorporate the kernel with camera driver into an image of your design.

$ cd ~/overo-oe/org.openembedded.dev
$ git pull origin overo
$ bitbake linux-omap3-caspapx

When the build completes, the kernel and modules will appear in ~/overo-oe/tmp/deploy/glibc/images/overo.

== Customization ==

This section describes how to customize the camera driver and kernel for your needs.

=== 2.6.34 ===

Get the kernel source that is used in the Gumstix kernel recipe (~/overo-oe/org.openmebedded.dev/recipes/linux/linux-omap3_2.6.34.bb) and create a new branch from the recipe SRCREV.
$ cd ~
$ git clone git://www.sakoman.com/git/linux-omap-2.6.git
$ cd linux-omap-2.6
$ git checkout -b 2.6.34 cb89736af28f583598e49a05249334a194d00f1d

Get the patch.
$ wget http://cumulus.gumstix.org/sources/mt9v032-2.6.34.patch
$ patch -p1 < mt9v032-2.6.34.patch

Get the kernel configuration. This is the same one used for the linux-omap3-caspapx image.
$ wget http://cumulus.gumstix.org/sources/mt9v032-2.6.34.defconfig
$ cp mt9v032-2.6.34.defconfig .config

If you haven't done so yet, you'll need to [http://www.gumstix.net/Setup-and-Programming/view/Overo-Setup-and-Programming/Setting-up-a-build-environment/111.html set up your build environment]. Build the console image. This will ensure that the cross compiler, binutils, and libraries need to compile the kernel are installed.
$ bitbake omap3-console-image

Add the cross compiler to your path and configure the kernel. The cross compiler location depends on the architecture of your build machine.
''32-bit processors''
$ export PATH=/home/<username>/overo-oe/tmp/sysroots/i686-linux/usr/armv7a/bin:${PATH} 
''64-bit processors''
$ export PATH=/home/<username>/overo-oe/tmp/sysroots/x86_64-linux/usr/armv7a/bin:${PATH}

Build kernel and modules
$ make ARCH=arm CROSS_COMPILE=arm-angstrom-linux-gnueabi- uImage
$ make ARCH=arm CROSS_COMPILE=arm-angstrom-linux-gnueabi- modules

Install modules
$ mkdir ~/linux-omap-2.6/modules
$ make ARCH=arm CROSS_COMPILE=arm-angstrom-linux-gnueabi- INSTALL_MOD_PATH=./modules modules_install

=== Other Kernel Versions ===

The ISP code used for the 2.6.34 patch came from the arago-project. This is the OMAP3 PSP kernel integration/staging tree
$ git remote add git://arago-project.org/git/projects/linux-omap3.git aragoOMAP3 PSP kernel integration/staging tree
$ git fetch arago
$ git checkout -b arago

The V4L2 subdevice framework offers a way to configure the Image Signal Processor pipeline from user-space. This is currently under active development and users wishing to make use of this should visit the Media controller development repository [http://git.linuxtv.org/pinchartl/media.git here]. This contains the bleeding edge Video for Linux media framework, ISP, and MT9V032 drivers.

=== MT9V032 Driver ===

If you want to take advantage of an unimplemented sensor feature, change defaults, etc., you need to modify the driver source. After you've made a change you can use a script like the following to quickly test your new driver.

#! /bin/bash 
TARGET_OVERO="root@10.0.1.15"
make -j8 ARCH=arm CROSS_COMPILE=arm-angstrom-linux-gnueabi- modules
ssh $TARGET_OVERO 'rmmod mt9v032'
scp drivers/media/video/mt9v032.ko $TARGET_OVERO:/lib/modules/2.6.34/kernel/drivers/media/video/
ssh $TARGET_OVERO 'insmod /lib/modules/2.6.34/kernel/drivers/media/video/mt9v032.ko'
ssh $TARGET_OVERO 'mplayer -display :0.0 tv:// -tv driver=v4l2:device=/dev/video0'

=== Image Signal Processor ===

There is some code that you can't modularize and modifying means rebuilding the kernel. Such is the case for the ISP code which is used by board-overo.c for hardware configuration. Another script like that in the previous section can be very useful.

This script rebuilds the kernel, copies it to the COM, and resets:

#! /bin/bash 
TARGET_OVERO="root@10.0.1.15"
make -j8 ARCH=arm CROSS_COMPILE=arm-angstrom-linux-gnueabi- uImage;
scp arch/arm/boot/uImage $TARGET_OVERO:/boot/uImage;
scp arch/arm/boot/uImage $TARGET_OVERO:/media/mmcblk0p1/uImage
ssh $TARGET_OVERO 'shutdown -r now'

This is useful for adjusting the filters, white balance, and color blending coefficients used by the ISP preview module. The preview module is used for doing hardware conversion from 10-bit Bayer to YUV. If you are having color problems - especially under certain lighting conditions but not others - look at '''isppreview.c''' and the gamma correction tables in '''drivers/media/video/isp/'''

== Tuning ==

=== Module Parameters ===
By default, auto exposure, auto gain, and high dynamic range are all enabled. You can disable any or all of these to suit your needs by reloading the driver.

Get a list of driver parameters.
# modinfo mt9v032
filename: /lib/modules/2.6.34/kernel/drivers/media/video/mt9v032.ko
license: GPL
author: Ignacio Garcia Perez <iggarpe@gmail.com>
description: mt9v032 camera sensor driver
srcversion: A46920FD64C35A2645E0D54
alias: i2c:mt9v032
depends:
vermagic: 2.6.34 mod_unload modversions ARMv7
parm: sensor_type:Sensor type: "color" or "mono" (charp)
parm: auto_exp:Initial state of automatic exposure (int)
parm: auto_gain:Initial state of automatic gain (int)
parm: hdr:High dynamic range (int)
parm: low_light:Enable companding (int)
parm: hflip:Horizontal flip (int)
parm: vflip:Vertical flip (int)

Depending on the light level, auto exposure might reduce the framerate as low as 15 frames per second. You can disable auto exposure like so:
# rmmod mt9v032;
# insmod /lib/modules/2.6.34/kernel/drivers/media/video/mt9v032.ko auto_exp=0

If this makes your image too dark, you can disable auto gain and enable companding mode (more information [http://www.aptina.com/assets/downloadDocument.do?id=668 here]).
# rmmod mt9v032
# insmod /lib/modules/2.6.34/kernel/drivers/media/video/mt9v032.ko auto_exp=0 auto_gain=0 low_light=1



== External Links ==

Caspa VL (filtered lens): [http://www.mars-cam.com/optical/lenses/ccd_cmos/43fix.php V-4303.6-1]

Caspa FS (unfiltered lens): [http://www.ktnc.co.kr/english/viewtopic.php?t=468 KLB-0360]

[http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=spruf98m&fileType=pdf OMAP35x Technical Reference Manual]

[http://www.aptina.com/assets/downloadDocument.do?id=668 MT9V032 Datasheet]

[http://pubs.gumstix.com/boards/CASPA/PCB30009-R2496/ Caspa layout and schematic files]

[[Category:How_to_-_expansion_boards]]