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DLPDLCR2000EVM: Color temperatures are warm overall.

Rohan Asokan
Prodigy 10 points
Part Number: DLPDLCR2000EVM

Hi!

The color seems very warm in the splash screen image or when connected to a BBB. Especially whites look very off. I require B&W mode, is there a way I cam use the grayscale color map with 2000EVM? And in general, how do I reduce the warmness? I have tried redshift to no avail.

I am on Debian 10 with LxQt and no other changes to the configuration.

Thanks.

  • 0
    Prodigy 10 points

    I will add to this the experiments I have tried using I2C. I try to set the pattern to pure white using an internal pattern projector and then try to set up WPC control at 0x7 - meaning everything with WPC without Fast WPC algorithms. It worked one time by magic and every other time I repeat the same order of commands after reboots, I am unable to replicate it. When I say it worked, it projected a pure white image without any warm or cold undertones.

    debian@beaglebone:~$ i2cset -y 2 0x1b 0x0b 0x00 0x00 0x00 0x01 i
    debian@beaglebone:~$ i2cset -y 2 0x1b 0x0c 0x00 0x00 0x00 0x1b i
    debian@beaglebone:~$ i2cset -y 2 0x1b 0x11 0x00 0x00 0x00 0x02 i
    debian@beaglebone:~$ i2cset -y 2 0x1b 0x16 0x00 0x00 0x00 0x07 i
    debian@beaglebone:~$ i2cset -y 2 0x1b 0xb5 0x00 0x00 0x00 0x07 i

    These are the exact set of commands (in order - set to internal projection pattern, set resolution to nHD, set pattern type to plain white, set all LEDs to turn on, switch on WPC with led power control).

    Worked once and never again.

  • 0 in reply to Rohan Asokan
    TI__Expert 3905 points

    Hello Rohan,

    Welcome to the E2E forum. Thank you for your business!

    Can you confirm that the individual LEDs are functioning as expected? Set the pattern to plain white but send the I2C commands to toggle each LED one at a time. See Section 2.4.1.11 of the DLPC2607 Programmer's Guide for your reference.

    Best,

    Maxine

  • 0 in reply to Maxine Cabrasawan
    Prodigy 10 points

    Hi Maxine,

    I have done more experiments after that, it seems this issue is present accross all PWM ranges of each LED. What I've found is 127,127,511 and 255,255,1023 are good pwm values for RGB respectively. And yes individually they work great. What is especially weird is at lower pwm with the same ratios as above for example 63,63,255 or 31,31,127 the yellowish tinge comes back. I have sety ratios to 127,127,511 and it's quite close to white.

    Could this be an issue with the red and green components of the driver? Or is there some other setting that could be interfering? This color profile is how it came out of the box.

    Is there any calibration script that I can run? Maybe that might help.

    Thanks

    Rohan Asokan

  • 0 in reply to Rohan Asokan
    TI__Expert 3905 points

    Hello Rohan,

    It is possible that parallel video GPIOs are not sending data as they should. Load up an RGB color ramp to verify which, if any, GPIOs are not functioning correctly.  Examine the 256 individual codes to determine where the colors are incorrect. 

    The EVM has an internal test pattern generator that includes this ramp pattern. You can compare these ideal outputs to your discolored images to help identify the problem areas.

    To access the internal test pattern generator, issue the appropriate I2C commands - 0x0B (source select), 0x0C (resolution select), and 0x11 (test pattern select).

    Best,

    Maxine