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element14: BB-VIEW LCD Cape for BeagleBone Black and CANBus Cape CircuitCo

Former Member

Hello,

 

I am new in linux/arm programming and my English is not the best. So I hope you will understand my problem:

I want to use the BB-View for the BeagleBone Black to display some CAN signals. To get the signals from the CAN bus I use the CANBus Cape from CircuitCo. My problem is, after I installed the BB View Angstrom Image File, the Display is working but I dont get the CANbus Cape working. The problem is that the LCD and the CANCape use two same Pins of the P9-Header (Pin94 and Pin97):

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I wanted to install the CANCape with a dts/dtbo-File as an overlay. The Failure I get is, that the pin 97 is already used by the LCD-Display.

So my question is, how I get this pin "uninstalled" for the LCD, so I can use it in my overlay for the CANCape. I hope you understand my explanation.

Thank you for your help.

 

Moloch

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  • 0

    If the pins used by the two capes conflict, then your only choice is to use one at a time. You'll be unable to use both simultaneously.

     

    Looking at the two you've highlighted it would seem that if you were to decide that you don't need the Led or User1 switch then you could still have the LCD working.

     

    I'd think you may need to physically remove at least the Led from the board to stop it causing problems for I2C2_SDA, and personally I'd remove the button if it's going to be physically accessible. There may also be a pull up/down resistor associated with the switch that you'd want to remove, but as we haven't seen schematics for the BB-View that's just a guess.

     

    You'd then either need to build a new dtbo for the LCD cape with those two pins removed, or simply ditch capemgr altogether and build a single fixed dtb that fits your purpose.

     

    Also, if you don't already know, Angstrom is being replaced with Debian on the BBB. Might be worth looking at moving away from Angstrom.

    http://www.element14.com/community/thread/32106/l/beagleboardorg-releases-debian-for-beaglebone-black

  • 0 in reply to Former Member

    First, thank you for your fast answer.

    Second, thank you for your advice to remove the physical components. But first I think, I have to change the "software". To get the LCD-Display work, I had to download the BB View Angstrom Image File from http://www.element14.com/community/community/knode/single-board_computers/next-gen_beaglebone

    The problem is they change the angstrom distribution with a dtbo file. I have no Reader for this files and a dts file is not given. So is there any possibility to change this dtbo file? I dont know what they all changed, that the LCD work...

    Btw the User Manual for the Installation you can find here http://www.element14.com/community/docs/DOC-55844?ICID=knode-beagleboneblack-space

    I am not sure if I would get the LCD working on Debian. I hope you can already follow my explanations :-)

     

    Regards

     

    Moloch

  • 0 in reply to Former Member

    Modifying the software is fairly easy.  My recollection is that the dtbs are in one of the BB-View downloads somewhere.  Regardless, you can use the device tree compiler to get back to a dtbs file.  You do something like "dtc -I dtb -O dts file.dtbo > file.dts" - I might have the syntax slightly wrong as I don't have access to a system with it installed right now.  When you've done the changes you recompile it with "dtc -@ -I dts -O dtb file.dts" the -@ is important as is having the correct version of the compiler. It's the -@ which adds proper support for run-time symbol resolution as required by overlays.

     

    I'll also suggest you have a read at the following two discussions:

    http://www.element14.com/community/thread/31051/l/how-to-bb-view-on-latest-debian

    http://www.element14.com/community/thread/30835/l/bb-view-7-on-bbb-with-debian-or-ubutun-or-buildroot

     

    I'm sure they won't answer all the questions you might have, but they do contain a lot of useful information for using the BB-View boards... We've done a lot of the hard work already image

  • 0 in reply to Former Member

    Thank you very much!!! till now ;-)

    To compile the overlay for the CANBus Cape I used this: "dtc -O dtb -o BB-DCAN1-00A0.dtbo -b 0 -@ BB-DCAN1-00A0.dts".

    This are the files, are needed to install:

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    I think to solve my problem I need to compile the am335x-boneblack.dtb and am335x-boneblack-lcd7.dtb into dts files?

    So the command would look like this: "dtc -O dts -o am335x-boneblack.dtb -b 0 am335x-boneblack.dts"

    I can test it on monday, then I am back at work ;-)

    I will read the discussions the next days. Btw. if I click on discussions, I can't see all the topics :-( Not sure why...

  • 0 in reply to Former Member

    Hello again,

     

    after I tested a bit, I am not sure what I have to do next... So I will ask you now again...

    What I did:

    1. I changed the BB-VIEW-LCD7-01-00A0.dts file (I found it under /lib/firmware/), so that the pins I want to use for my CAN-Cape are not used anymore by the BB-View LCD. First I tested it by just change it after installing the modified kernel given by element14. Next I tried to install the CAN-Cape, but the system told me, that the

    Pin 97 is still used bei the LCD...

    2. The next thing I tried (I used a new clear angstrom distribution on other sd-card), was to just copy the am335x-boneblack-lcd7.dtb to /boot/ as am335x-boneblack.dtb and to copy the modified BB-VIEW-LCD7-01-00A0.dts to /lib/firmware/. The LCD worked but without "touch", I just got the picture. I installed my CAN-Cape and it worked also. But without the touch-function the dispaly is a bit useless -.-

     

    So now I tried to understand the following post:

    http://www.element14.com/community/thread/31051/l/how-to-bb-view-on-latest-debian

    But I am not sure how I can get the touch working...

    I think I have to recompile the kernel (given by element14)? Problem is, if I do that, I cant change the Pin97 and I cant use the CAN-Cape... I dont know in which files, except the .dts/.dtbo files in /lib/firmware/, I can change the pins... The problem is, that I can't read the files, which are in "kernel_modules.gz".

     

    Thanks for help.

     

    Moloch

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  • 0 in reply to Former Member

    Hello again,

     

    after I tested a bit, I am not sure what I have to do next... So I will ask you now again...

    What I did:

    1. I changed the BB-VIEW-LCD7-01-00A0.dts file (I found it under /lib/firmware/), so that the pins I want to use for my CAN-Cape are not used anymore by the BB-View LCD. First I tested it by just change it after installing the modified kernel given by element14. Next I tried to install the CAN-Cape, but the system told me, that the

    Pin 97 is still used bei the LCD...

    2. The next thing I tried (I used a new clear angstrom distribution on other sd-card), was to just copy the am335x-boneblack-lcd7.dtb to /boot/ as am335x-boneblack.dtb and to copy the modified BB-VIEW-LCD7-01-00A0.dts to /lib/firmware/. The LCD worked but without "touch", I just got the picture. I installed my CAN-Cape and it worked also. But without the touch-function the dispaly is a bit useless -.-

     

    So now I tried to understand the following post:

    http://www.element14.com/community/thread/31051/l/how-to-bb-view-on-latest-debian

    But I am not sure how I can get the touch working...

    I think I have to recompile the kernel (given by element14)? Problem is, if I do that, I cant change the Pin97 and I cant use the CAN-Cape... I dont know in which files, except the .dts/.dtbo files in /lib/firmware/, I can change the pins... The problem is, that I can't read the files, which are in "kernel_modules.gz".

     

    Thanks for help.

     

    Moloch

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