DLP4500: Issue with displaying video via HDMI port.

Hello Alexander,

Welcome to DLP forum and thank you for your interest in DLP technology. We will review it and get back to you.

regards,

Vivek

Thank you! I will be waiting for your answer.

Alexander

Hi Alexander, 

Can you please confirm that the raspberry pi output includes blanking intervals more than specified on the DLPC350 Datasheet  section 6.11 Video Timing Input Blanking Specification?

Also, could you please try connecting the LCR4500 EVM to another source (such as HDMI out from laptop/ PC) and see if you can get image on the wall?

Thanks & Regards,

Hirak.

Hello Hirak,

Yes, I was configuring custom hdmi model on rasperry referring to DLPC350 Datasheet section 6.11. I think that i can attach model parameters with desription.

hdmi_timings=800 1 20 20 68 600 1 4 20 388 0 0 0 60 0 28800000 3, where

1 <h_active_pixels> = 800 (width)
2 <h_sync_polarity> = 1
3 <h_front_porch> = 20
4 <h_sync_pulse> = 20
5 <h_back_porch> = 68 
6 <v_active_lines> = 600
7 <v_sync_polarity> = 1
8 <v_front_porch> = 4
9 <v_sync_pulse> = 20 
10 <v_back_porch> = 388 
11 <v_sync_offset_a> = leave at zero
12 <v_sync_offset_b> = leave at zero
13 <pixel_rep> = leave at zero
14 <frame_rate> = 60
15 <interlaced> = leave at zero
16 <pixel_freq> = 28800000  (width*height*framerate)
17 <aspect_ratio> = 3 (16:9)

Actually, we have a custom electronic board and I assume we may have some problems with EDID EEPROM, because it's empty, and we may need a EEPROM firmware file for DLP, because it's hard to configure.

Thank you,

Alexander.

Alexander,

Thanks for sharing your Raspberry Pi configuration. Do you have the full config.txt file? 

Hello Philippe,

For sure, i can share my Raspberry config file in attachments.

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87
hdmi_timings=800 1 20 20 68 600 1 4 20 388 0 0 0 60 0 28800000 3

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2c2_iknowwhatimdoing
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
start_x=0

To add, I got this config tested by Raspberry Pi support engineer, he answered that it works correctly (but he got it tested on the HDMI capture card).

Regards,

Alexander

Hi Alexander, 

Can you please try with another source such as your laptop/PC? That will confirm once & for all if there is something wrong with your EVM. Also, did you modify the TI FW Image (adding custom Images, I2C Settings, Config INI etc)  in any way before flashing it on to the device?

Hi Hirak,

Yes, I've already tried to connect DLP to another source - and the streaming was successful. Also, I did try to add custom images but nothing was displayed

Regards,

Alexander

Hi Hirak,

Thank you for your answer and providing information about types of GUI, it really helped. I've installed correct version for FW v.4.1., but still there's no stream on DLP and resolution's still to be inaccurate.

Blanking information from the device with successful streaming is attached, still no result from applying same params to RPi module.

Regards, 

Alexander

Alexander,

I noticed that your Raspberry Pi config.txt uses the old timings (28 MHz), and that the above timing does not work. What happens when you use the above timing configuration on the Raspberry Pi:?

Philippe,

Thank you very much for your help, I've managed to resolve my issue with changing config input interfaces.

Regards,

Alexander