[How-to] BB-View on latest Debian

Regarding Patching the Kernel:

My "touchscreen" is in your linux-dev repository, but not in the angstrom source.  Should we do the cp FROM your linux-dev repository TO the ANGSTROM source?

I pulled the source directly from the Element 14 site, and the file (unzipped) was:  bb-black-kernel-3.8.13-bb-view.tar.bz2.  It doesn't seem to have these files.  If your source already has them, why are we rebuilding the Kernel?

Also, with the addition of the LCD line to the Makefile, can you id where it needs to go (functionally), rather than just mentioning a line numbers, so I know I have this right?

Thanks.

> unzip angstrom-source.zip

> tar -zxf bb-black-kernel-3.8.13-bb-view.tar.bz2

> cp ./kernel/kernel/drivers/input/touchscreen/ti_am335x_tsc.c  ~/bb-view/linux-dev/KERNEL/drivers/input/touchscreen/

> cp ./kernel/kernel/firmware/capes/BB-VIEW-LCD7-01-00A0.dts  ~/bb-view/linux-dev/KERNEL/firmware/capes/

@Matthew Trippy

Is the rest of the Angstrom source visible? Are the other source folders present and populated?

The reason for copying the angstrom tsc file to the linux-dev was to get most of the changes copied over to the Debian build under linux-dev. You are not building Angstrom, so you don't need to copy from the linux-dev folder back to the Angstrom folder.

The reason for compiling the kernel is to enable touchscreen support. If you don't need the touch screen controller, you don't have to recompile. The LCD7 uses a non-standard connection method, so the analog pins have to be read in a different order, by the tsc driver.

The makefile line placement is not critical. I just included it close to where the other dts files where getting added, so I could find it again if I needed to change anything.

Louis

I'll need to get back to the board later tonight, but what should I do if the backlight.11 directory isn't populated?  Can I manually change/add any settings there?  I did get a "brightness error at startup (I can't find it now, but it basically said the setting was 101, which was not allowed, so it is setting the display to 100)

don't worry about the 100 vs 101 message, I see that too. It's just one of the settings in the dts file and could be fixed fairly easily. It won't stop the lcd from functioning.

I was more interested in whether the "ehrpwm 48302200.ehrpwm: unable to select pin group" line had caused the driver not to load. However even if the driver has loaded, that message could imply that the pin hasn't been configured.  Working that out will be more involved unless you have a scope handy.

I'll need to get back to the board later tonight, but what should I do if the backlight.11 directory isn't populated?  Can I manually change/add any settings there?  I did get a "brightness error at startup (I can't find it now, but it basically said the setting was 101, which was not allowed, so it is setting the display to 1

OK - time for the dumb question now.  My BB-View indicated that the J1 connector was for the BB, and the J2 connector was for the BBB.  Since the J2 was foam/glued lightly to the underside of the display, and that was the end you pull out to connect to the BeagleBone Black, I naturally assumed the same was the case for J1, so I pulled the smaller ribbon cable, and then disconnected it from J2.  Except I directed a flashlight into the space, and there was a connector that it appeared to be slipped into, rather than just taped/glued.  No locking mechanism, just the slider.  So it came out easily.

Does the J1 connector need to remain connected, even though I'm using J2?

You mean on the paper 'Quick Start Guide' where it says "Connect the BB View: Connect the BB View to the BeagleBone or Beaglebone Black using the 46 pin dual-row connectors (J1 and J2)" ?

J1 & J2 are the two 46pin headers on the cape

If you've disconnected something else then yes you will likely have a problem.  What problem is hard to tell, maybe the backlight, maybe the touchscreen..  How many connections in the one you removed ?  If it's four then it could be the touchscreen.

No.  Not on the header.  On the 7" LCD.  The ribbon cables for both J1 and J2 are connected via the clamps, to each connector.  When you take it out of the box, the J2 is wrapped around and foam/taped to the underside of the LCD, just on the edge.  I thought the J1 was the same, so, since I'm using J2 and the larger ribbon cable, I pulled (lightly) on the smaller ribbon cable, and it came loose the same way.  Only I double checked with a flashlight, and that smaller ribbon cable does actually have a connector on the underside of the board.  This cable doesn't need to be looped around and remain in the J1 connector does it?  For some sort of continuity?

                  Left connector is J2.  It goes to my BBB

                          |                             Right connector is J1 (not connected)

                          |                                  | 

                         \/                                 \/

                                                /\

                                                 |

Underside of 7" LCD display - this is a connector, not just a foam/tape!

The ribbon cable for J1 was "plugged in", and wrapped around the board

and connected to J1

Ah.. I have the 4.3" one. Nothing like that on mine.  Someone with a 7" one might be able to help.

Back of the 4.3" one looks like this

the white cable to the right goes to the cape.  I take it this is totally different to the back of the 7" one ?

Here's the board.  So I'm on a wild goose chase I think.  The J1 connected ribbon cable should probably have been taken out.

I'm reflashing my Debian ARM image.  I'm thinking I corrupted the image when I didn't wait until the 4 lights came on.  It seemed like

a long time (>45 min), and the 4 lights never came on.  But when I restarted on my HDMI, I saw the penguin, so at least part of

the image was flashed.  It never let me logon though, and the screen went blank, so the disable HDMI is working, but it's not starting up the LCD. I need to be

able to SSH into the BBB, or otherwise start over I guess.

> 45mins was common with the Angstrom images, but from what I've read it should be approx 15mins with debian.

if the HDMI disable has worked properly, then in theory you shouldn't see anything on the HDMI output as that driver won't load.  However as the LCD and HDMI framer share the same set of pins I suppose it's possible to have output on both if the timings work out and the monitor, by some miracle, supports the same timings.

To be sure you properly boot from the uSD to flash, be sure to remove power, hold the boot button, then apply power. The state of the button is only sampled at power-on, not reset, and the sampled state survives a reset, so you keep booting from uSD until you power cycle again.

OK.  New power supply.  I was using one that was older, though the specs were 5A, it seemed the lights were dimmer than using USB power.  This one is w/ the DC connector, and 3.5A 5VDC.  Lights seem brighter now.  Not getting anything on the display, not even a backlight.  Blue lights are blinking, Blue power light is on and bright.  On the cape, I noticed that the Green light is solid, but the red light (LED0) is off now.

OK.  New power supply.  I was using one that was older, though the specs were 5A, it seemed the lights were dimmer than using USB power.  This one is w/ the DC connector, and 3.5A 5VDC.  Lights seem brighter now.  Not getting anything on the display, not even a backlight.  Blue lights are blinking, Blue power light is on and bright.  On the cape, I noticed that the Green light is solid, but the red light (LED0) is off now.

Interesting.  I seem to remember that one of the LEDs on the cape was configured as heartbeat.  Perhaps that was the TI-SDK image then as looking at the overlay files I see:

gpio-leds-cape-lcd {

  compatible = "gpio-leds";

  pinctrl-names = "default";

  pinctrl-0 = <&bb_view_lcd_cape_led_pins>;

  bb_view_led0 {

    label = "bb-view:led0";

    gpios = <&gpio2 28 0>;

    linux,default-trigger = "none";

    default-state = "off";

  };

  bb_view_led1 {

    label = "bb-view:led1";

    gpios = <&gpio1 12 0>;

    linux,default-trigger = "none";

    default-state = "off";

  };

};

which implies they should both be off.

Are you able to ssh into the board, or to use a console cable?

If you are, you can look see if /sys/class/leds has bb-view:led1 & bb-view:led2 if those dirs exist, you can go into one of them and type "echo heartbeat > trigger" which should result in that led flashing a heartbeat pattern. Should that work the overlay would appear to be loaded ok.

Matthew Trippy wrote:

 

OK.  New power supply.  I was using one that was older, though the specs were 5A, it seemed the lights were dimmer than using USB power.  This one is w/ the DC connector, and 3.5A 5VDC.

As an aside, if your power supply is of the 'USB Charger' type, I'd refer you to the experiences of the Raspberry Pi people who found that the specs on the label on most of them simply can't be trusted...

A decent PSU is likely to be necessary with the LCD connected as you have and additional thing to power.