• Resolved

DLPDLCR2000EVM: EVM with Raspberry Pi3 B+ Screen Flicker / Glitch Issue

Prodigy 200 points

Replies: 15

Views: 387

Part Number: DLPDLCR2000EVM

When I connected Raspberry Pi 3B+ with EVM 2000, I can able to see the desktop, but the screen is flickering / glitch. I saw a related article about changing the GND pin from EVM to Rpi3 pin 6 (GND).

https://e2e.ti.com/support/dlp/f/94/t/700072

I don't understand which GND pin from EVM? Please provide the exact pin number. There are 5 GND pins in EVM P2 side.

  • Hello Gopinathan,

    The ground of the Pi should be connected to the ground of the EVM so the signals have a common ground. It doesn't matter which specific ground pin on the EVM is used as all of the grounds are electrically the same.

    Thanks,

    Kyle

  • In reply to Kyle Rakos:

    Thank you Kyle.

    Is ang other troubleshooting guide to solve the screen flickering issue ?

    This is annoying for me. Initially I tried with BeagleBond black, I felt the performance is not good, unable to play video or browser smoothly.

    Later I integrated with Pi 4B, but the display never turned ON, i2c detects on address 7 instead of 3.

    Again I tried with Pi3B+, now everything is Ok, except the flickering issue.

  • In reply to GOPINATHAN M:

    Hello Gopinathan,

    Did you attach the grounds of the two units? Additionally, if a different address is detected it should be simply changeable by software.

    Thanks,
    Kyle

  • In reply to Kyle Rakos:

    Hi Gopinathan,


    If you still need assistance please let me know. For now I will mark this thread resolved.

    Thanks,
    Kyle

  • In reply to Kyle Rakos:

    Hello, I think I have the same issue:

  • In reply to Maxim Khazanov:

    Maxim,

    The issue above is very likely due to timing issue between the Raspberry Pi and BBB. The two easiest ways to resolve this:

    > Relax video timings in the config.txt of Raspberry Pi

    > Use an adapter board (such that this one from MickMake https://www.tindie.com/products/mickmake/pi-projector/) or equivalent to interface the systems without using jumpers

    If you cannot do the above, you should check your jumpers and try to ensure they are all as close in length as possible to avoid timing problem.

    I hope this helps.

    Best Regards,

    Philippe Dollo

  • In reply to Philippe Dollo:

    Thanks for the update. 

  • In reply to Philippe Dollo:

    Thank you for reply, I checked the timings (made according to w*h*60 fixed the glitch)

    But I'm getting this result with 854x480 resolution. With 720x480 it works with 0x0c to 0x09 at i2cset, but not using full width.

    According to DLPC2601 Programmer's guide,  it supposed to be 0x0c set to 0x19 for 854x480 but it gives something like 640x480 and strangely works with 0x13, but gives this issue from screenshot.

    I'm looking forward for your recommendations

  • In reply to Maxim Khazanov:

    Maxim,

    I've personally tested this behavior on a Raspberry Pi and produced a similar result as you.

    In this case, choosing the incorrect resolution (on purpose) does appear to somehow accommodate the problems introduced by using jumpers for the Raspberry Pi connection. However, this does not resolve the root cause.

    Changing the setup to use a PCB adapter along with a GPIO ribbon cable results in a much more stable connection. For further optimization, I also recommend adjusting the GPIO drive strength on your output:

    > gpio drive 0 #

    Where # is the desired drive strength (from 0 to 7). I hope this helps.

    Regards,

    Philippe Dollo

  • In reply to Philippe Dollo:

    Philippe, thanks for your reply.

    I didn't expect any more answers in this tread so I opened a new one: https://e2e.ti.com/support/dlp/f/94/p/850392/3155530#3155530 with my own reply at the end of how I fixed that. 

    May I ask here if you know something about color banding issues?

    Regards,

    Maxim