PB LCD

I am trying to get an LCD - the same one as the 4.3" CAPE working on a PB derived board.
Everything is hooked up the same.
I have copied BB-CAPE-DISP-CT4-00A0.dts
and changed the pins to match PB
It is loading but no display, no backlight.

PB-LCD-MTS.dts (8.38 KB)

Dave,

I presume by PB you mean Pocketbeagle.

Assuming the above and looking at the .dts file, I do not think this will work. I could easily be wrong, but the way I read the .dts file, you are trying to use the LCD output pins from the am335x (mode 0). On the Pocketbeagle those pins do not go to any connector output pins (P1 or p2). You said a PB derived board, so maybe on that board the LCD pins do go to the output pins but I cannot tell without seeing a copy of that board’s schematic.

Graham

The board is PocketBeagle derived - it is not a PocketBeagle.
It just starts with the PcoketBeagle design rather than the BBB.

It removes lots of things that are not used - such as P1 and P2,
And adds a bunch of things that are needed - such as the LCD.

Some of what is added is added similar or even identical to how it is in the BBB rather than the PB.

One of the software headaches I have with this project is that the software development and prototypes were all BBB’s and BBBW’s.

But the first spin production boards are PB design derivatives - but with things like the rough equivalent of a BBB 4.3 LCD display CAPE added.

To get the board to boot - I am using the PB base device Tree. It will not boot using a BBB deviceTree.

But it appears I need to go further and strip out of the PB device tree stuff like P1 and P2 that I do not have.

Hi Dave,

Did you succeed to make the LCD work on your board?

Can you send me details of your board? Where did you buy it? I also would like to have a pocketbeagle board, with LCD.

I bought a pocketbeagle and I’m waiting it to arrive, but I found that the LCD pins are not connected to the expansion headers after buying it. Since they are the same pins connected to the boot configuration, we have them exposed on the board connected to the resistors close to the main chip and I hope I can hook some wires to connect an LCD, but I don’t know if there something else that I have to do, like in the software side (apart of the BBB driver) to say to the board that I want video output to the LCD pins.

Best

Hello Dave,

I echo the same interest. We wish to work with a pocket beagle also. An LCD screen would be nice to get visual feedback. Who is the maker/ vendor and what is the part number of the board?

Regards.

Although it isn’t the 4.3" CAPE, I have gotten a generic and inexpensive 2.8" ILI9348-based SPI display to work with the Pocketbeagle (and Beaglebone black). It seems reasonably fast although I’m sure not as fast as the parallel display. I haven’t yet gotten the built-in TSC2046 resistive touch controller to work yet. I’ve attached the dts file for the display. You can see how I wired it up at the following github page:

https://github.com/danjulio/lepton/tree/master/pocketbeagle

PB-TFT-ILI9348-SPI0.dts (7.23 KB)

Hi Dan,

thank you to share your project, really nice :slight_smile:

I saw that you used the standard pocketbeagle. I also noticed that you are the author of a hackday.io article about the PMU inside the pocketbeagle which I’m also interested in that.

Like you, I also have a project that uses the Rpi zero, and I needed to stop working on that due to the workarounds that I had to do to make it a portable system. The Rpi doesn’t support any kind of low power modes (sleep, suspend to RAM …), doesn’t have PMU and we have to use SPI or HDMI to drive an LCD display which is a problem in performance, and power efficiency.

I saw on the beagleboards a light because we have the PMU, and an LCD driver ready to use without any proprietary firmware, I don’t need HDMI output and I don’t want to waste power to feed HDMI IC’s. Everything with a trully open hardware system is a dream! Also with the Octavo system in a package, I could design a more professional system without been too complex for a hobbyist point of view, and maybe I could even try to solder the BGA chip myself. So, now I have space to work in my software and If everything goes well I could even try to go to a customized board.

So, the pocketbeagle seemed a good start to work, but the lack of the LCD pins and the things that you mentioned in your article about the PMU really broke my legs. The BBB (standard, and Wireless) are big boards, has many things that I don’t need and will consume my power resources. Would be a good addition to have wifi (and switch it off when it is not needed), but the wireless version doesn’t have wifi when working on battery…

When my boards arrive, next week, I will work on the BBB wireless before, and in the future, I will try to hook some wires from the resistors that configure the boot, and see if I can drive an RGB LCD. I really don’t want to go to SPI LCD’s for now, maybe just to try.

Have a good weekend.

Best regards,

João,

Thank you for the kind words. Good luck with your project of adding a display to the PB. You should definitely share that here if it is successful.

I agree that the Octavo SIPs make it easy to contemplate making a custom board. I actually corresponded with them and they were testing one of the SIPs that had different PMIC wiring that would allow true battery operation (charging while system powered down). But I never heard if they finished testing this. I wanted to make a board using that device and a cellphone LCD/cap touch screen. I thought (still think) it would be a useful addition to the SBC world.

Cheers, Dan