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DLPDLCR2000EVM: Raspberry pi configuration using dtoverlay=vc4-kms-dpi-generic (raspberry pi os 12 bookworm)

Part Number: DLPDLCR2000EVM
Other Parts Discussed in Thread: DLP2000

Hi,  I am trying to configure the projector kit using the dtoverlay vc4-kms-dpi-generic in raspberry pi os bookworm lite. I am having issue finding the right parameters. I am using the projector with a resolution of 640x360, with the rgb666 format. It is working very well with the dtoverlay dpi18. I am using a custom pcb board so communication is not an issue.

The dpi generic is using rgb666 as default, and I translated the configuration of hdmi_timing and dpi_output_format from dpi18 to the new overlay format, (horizontal front porch, hsync, etc) so the config.txt now has the dpi18 commented out, and a new entry after the vc4-kms-v3d overlay :

*******************************
[...]

#dtoverlay=dpi18

#overscan_left=0

#overscan_right=0

#overscan_top=0

#overscan_bottom=0

#framebuffer_width=640

#framebuffer_height=360

#enable_dpi_lcd=1

#display_default_lcd=0

#dpi_group=2

#dpi_mode=87

#dpi_output_format=458773

#hdmi_timings=640 0 14 4 12 360 0 2 3 9 0 0 0 60 0 13824000 3

dtoverlay=vc4-kms-v3d
max_framebuffers=2

dtoverlay=vc4-kms-dpi-generic, clock-frequency=13824000
dtparam=hactive = 640, hfp=14, hsync=4, hbp=12
dtparam=vactive=360,vfp=2,vsync=3,vbp=9

#this shoulb be ok, but it seems to be worst
#dtparam=hsync-invert=1, vsync-invert=1
#dtparam=de-invert=1,pixclk-invert=0

*****************************************************************

with these parameters, I get an image, but it has some horizontal skewing, that can be work depending of the current content :, 

 

 

This is problematic. I can't use the correct parameters for the polarity hsync-invert, vsync-invert and de-invert without messing up completly the image. Did someone succeeded to configure the raspberry pi with this overlay? or even better, created a new overlay merged from the vc4-kms ?

*note, I can't revert back to dpi18 and commenting out vc4-kms-v3d. It prevents the libcamera from working.

  • Hello Nic,

    Welcome to the E2E forum and thank you for your interest in DLP® technology.

    Unfortunately the Raspberry Pi is not a host processor that we officially support for the DLP2000EVM. It may be possible to find support for this project online, but we will not be able to support this request in this forum.

    Kind regards,

    Austin

  • I resolved my issue by backtracking to the previous os, raspberry os 11 bullseye. the new release bookworm is not working with the dlp. With bullseye, I have perfect image, no tearing, and the libcamera library functionnal. To get a good image, the clock_frequency needs to be increased, I used 25000000. I can share the solution here, all details on my blog at intellar.ca. In short, you need is to add the dtoverlay vc4-kms-dpi-generic at the end of the /boot/config.txt, after the vc4-kms-v3d initialisation, important, no spaces between parameters :

    /boot/config.txt

         #init vc3-kms-dpi-generic overlay with dlp2000 parameters

         dtoverlay=vc4-kms-dpi-generic,clock-frequency=25000000

         dtparam=hactive=640,hfp=14,hsync=4,hbp=12

         dtparam=vactive=360,vfp=2,vsync=3,vbp=9

         #using custom board dlp0.1 check  intellar.ca  for details

         dtoverlay=i2c-gpio,i2c_gpio_sda=23,i2c_gpio_scl=24,i2c_gpio_delay_us=2, bus=1

    and I configure the dlp2000 on the fly with nHD landscape 640x360, and parallel interface, the same command TI used with the beagleboard, adding these line in rc.local:

    /etc/rc.local

        sudo i2cset -y 1 0x1b 0x0c 0x00 0x00 0x00 0x1B i

        sudo i2cset -y 1 0x1b 0x0b 0x00 0x00 0x00 0x00 i

    and the libcamera with the mipi pi hd camera is working !   Sorry for the distortion in this one, I'm using a close up lens to work closer to the wall.

      

    I have not given up on the OS bookworm, but I will let them iron out features before trying again. 

    nic

    intellar.ca

  • Hello Nic,

    Thank you very much for the information on your solution. We will mark this thread as resolved.

    Best,

    Maxine