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AM/DM37x EVM - switching video input options

Jignesh Shah
Prodigy 40 points

Other Parts Discussed in Thread: TVP5146, AM3715

Hi,

 

I am using AM/DM37XEVM Rev G. from Mistral with Android Gingerbread 2.3 and Linux kernel 2.6.32. Steps mentioned at http://code.google.com/p/rowboat/wiki/DSP are followed to build the Android - Kernel, Filesystem etc.

I have following questions:

1. What is default video input options - TVP5146, Micron Camera Connector, On board LI Module or Expansion Connector?

2. As per am3715_hug.pdf, it says Expansion connector is the default case. if that is so, then it says by switching T2_GPIO_2, T2_GPIO_8 and GPIO_157 i can switch between different video input options. But it does not say how and where to do that when Java as an application development language and android is used.

3. With TVP5146 camera input option, can i switch between RGB, Composite and S-video? if yes, how can be done?

with default connections, I am getting green screen on the LCD.

Regards,

Jignesh Shah

  • 0
    TI__Expert 8180 points

    Hi Jignesh,

    I may not be able to help you from Android interface perspective, I am not android expert...

     

    1. What is default video input options - TVP5146, Micron Camera Connector, On board LI Module or Expansion Connector?

    [Vaibhav] Two way of looking at default input, HW and SW perspective, and what user sees finally is SW default input. Until now we were supporting only TVP5146 video decoder input and which is enabled by default.

    Recently we have added Camera sensor interface (in YUV422 format) to the Linux kernel, but I am not sure whether Android is using it or not.

    2. As per am3715_hug.pdf, it says Expansion connector is the default case. if that is so, then it says by switching T2_GPIO_2, T2_GPIO_8 and GPIO_157 i can switch between different video input options. But it does not say how and where to do that when Java as an application development language and android is used.

    [Vaibhav] This is Android question, so I can help it out. From Linux perspective, these GPIO's are not exported to the user, what user sees is input (TVP5146 or sensor) and is controller through ioctl, which in turn controls these GPIO's to select and enable the requested input.

    3. With TVP5146 camera input option, can i switch between RGB, Composite and S-video? if yes, how can be done?

    [Vaibhav]With TVP5146 video decoder only 2 possible inputs are supported - CVBS ans S-Video.

     

    Thanks,

    Vaibhav

  • 0 in reply to Vaibhav Hiremath
    Prodigy 40 points

    Hi Vaibhav,

    Thanks for response.

    1. From the response, I understand that TVP5146 is default video input option with AM/DM37x EVM board. I tried connecting video camera to "CVBS in". With the default camera application in Android (built as descried in my earlier post), I am getting green screen on LCD. what could be possible solution to that?

    2. If GPIO is not exported to user space, how user can switch the video input options?

    3. how can i configure TVP5146 to switch between CVBS and S-Video from java application in android?

     

    Regards,

    Jignesh Shah

  • 0 in reply to Jignesh Shah
    TI__Expert 8180 points

    As I mentioned before, I am not an Android guy, so I can not help you in any of the Android related question. I will try to answer you from Linux point of view and let somebody from Android team answer from Android perspective -

     

    1. From the response, I understand that TVP5146 is default video input option with AM/DM37x EVM board. I tried connecting video camera to "CVBS in". With the default camera application in Android (built as descried in my earlier post), I am getting green screen on LCD. what could be possible solution to that?

    [Vaibhav] The reason behind green screen could be that, you are not getting any interrupts from AM37x ISP. This could be because, Android is not setting any inputs, configuration mis-match, etc...

    I will share one application (saMmapLoopback.c) with you, please try it at your end. I have tested it with plain Linux, I expect it to work on Android as well.

    Note: Works only if you are using 2.6.37 based kernel from TI.

    2. If GPIO is not exported to user space, how user can switch the video input options?

    [Vaibhav] Why do you want to control each GPIO from user space if driver takes care of it? And it does take care of complete path for requested input, if not, then its bug in driver.

    By the way, you can access the GPIO's through sysfs, if you want but I wouldn't recommend that.

    Also, I would suggest you to go through PSP user guide which explains about camera input in detail - http://processors.wiki.ti.com/index.php/UserGuideOmap35xCaptureDriver_PSP_04.02.00.07

    This should be your starting point....

    3. how can i configure TVP5146 to switch between CVBS and S-Video from java application in android?

    [Vaibhav] Sorry, Android question....I can't help here.

     

    Thanks,

    Vaibhav

  • 0 in reply to Vaibhav Hiremath
    Prodigy 40 points

    Hi Vaibhav,

    I appreciate your help.

    I am new to Android, I am little bit familiar with Linux to know how to do what I want to do.

    Loopback is not working without modifying anything that surprises me most. I am using AM/DM37x EVM as it is and following the steps given on the 2.1 Developer guide (http://processors.wiki.ti.com/index.php/TI-Android-GingerBread-2.3.4-DevKit-2.1_DeveloperGuide). I also tried steps given at rowboat (http://code.google.com/p/rowboat/wiki/DSP) with no better result.

    I hope someone familar with Android and DM37x EVM would like to help me out.

    Thank you again for your support.