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#1 2020-11-29 15:23:17

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Pi4B 4k 5.5" LCD CONFIG - HELP

OK, going to try again:

I have changed the guts to my Wanhao D7 Plus to a Pi4B and installed nanoDLP.  All is working, BUT for the 4k LCD.  The HDMI board flashes and does not change to a constant blue or green and no image appears.  This typically means that the HDMI board is not picking up the signal, in other words, the driver which I believe is the config file.  I have tested the LCD, MIPI and HDMI board on a laptop and it works fine.
Here is my config file, please can someone tell me what is or might be wrong and how to fix it.

Thank you.

# For more options and information see
# [url]http://rpf.io/configtxt[/url]
# 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=0
#overscan_right=1000
#overscan_top=50
#overscan_bottom=20

# uncomment to force a console size. By default it will be display's size minus overscan.
#max_framebuffer_width=1440
#max_framebuffer_height=2560
max_framebuffer_width=2160
max_framebuffer_height=3840

# Portrait or Landscape Setting
#framebuffer_width=1440
#framebuffer_height=2560

#Portrait-1 (Flexible cable is bottom side.)
display_rotate=0
#display_rotate=0x10000  was on 2k
framebuffer_width=2160
framebuffer_height=3840

# Landscape-1 (Flexible cable is right side.)
#display_rotate=1
#framebuffer_width=1920
#framebuffer_height=1200

# Portrait-2 (Flexible cable is upper side.)
#display_rotate=2
#framebuffer_width=1200
#framebuffer_height=1920

# Landscape-2 (Flexible cable is left side.)
#display_rotate=3
#framebuffer_width=1920
#framebuffer_height=1200

# 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

# uncomment to force a HDMI mode rather than DVI. This can make audio work in DMT (computer monitor) modes#
hdmi_drive=2
#hdmi_ignore_edid=0xa5000080

# 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=i2s=on
#dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

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

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

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2
hdmi_enable_4kp60=1

[all]

disable_camera_led=1
hdmi_pixel_encoding=2
start_x=0
gpu_mem=192
enable_uart=1

#Added by Jonathan Harrison#
force_trubo=1
gpu_freq=300
core_freq=400

# Wanhao D7 nanodlp config

# hdmi_pixel_freq_limit=500000000  was on 2k LCD config
hdmi_pixel_freq_limit=400000000
#hdmi_timings=1440 0 50 10 35 2560 0 4 2 2 0 0 0 50 0 198000000 0   was on 2k LCD config
hdmi_timings=2160 0 105 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

hvs_priority=0x32ff

framebuffer_depth=24
framebuffer_ignore_alpha=1
XMA Header Image

Last edited by Jonners59 (2020-11-29 16:54:32)


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#2 2020-12-02 07:52:59

Shahin
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Registered: 2016-02-17
Posts: 3,540

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Where did you get config.txt I do not think it match your LCD specs.
It takes time to adjust settings without getting proper configs from manufacturer.

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#3 2020-12-02 10:21:42

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

A long story.  I searched and got the D7 configs from various sources, just Google.  They are standard and worked perfectly, still does with 2k LCDs with the 2k timings and Frame info.  I had a helper when I started out who seemed and said he knew what to do.  He researched and came back with the 4k mods to the config - frame rates and timings, etc.  But still couldn't get it to work, and then I found that the

hdmi_enable_4kp60=1

code had to be added and it all lite up and worked.  Until there was a bang and I lost a few components.  After replacing them and moving to 24v it has not worked since, though 2k does now.

I am beginning to think that each HDMI board is different even if they look identical, so sticking to the same one from the same supplier is critical.  Same MIPI board and LCD.

I did get config code from one supplier later but that never worked even with their own LCD, HDMI board etc...  So not convinced they actually know what they are doing.  It didn't even have the hdmi_enable_4kp60=1 code included.

Have you tried the code, of any part of it like timings?  I have to say that every config for 4k I have found been sent has had the exact same timings and frame info.


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#4 2020-12-17 12:35:03

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Shahin wrote:

Where did you get config.txt I do not think it match your LCD specs.
It takes time to adjust settings without getting proper configs from manufacturer.

Any further thoughts, please?????


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#5 2020-12-17 17:48:11

Shahin
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Registered: 2016-02-17
Posts: 3,540

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

One of the things usually missing from these files on pi4 is :0= syntax. As I know you cannot use two high resolution display together. So you need to focus only setup one LCD output.
eg.
hdmi_pixel_freq_limit:0=400000000
hdmi_timings:0=2160 0 105 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

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#6 2020-12-18 10:44:13

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Shahin wrote:

One of the things usually missing from these files on pi4 is :0= syntax. As I know you cannot use two high resolution display together. So you need to focus only setup one LCD output.
eg.
hdmi_pixel_freq_limit:0=400000000
hdmi_timings:0=2160 0 105 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

OK, thank you.  Yes, I have seen it only does 4K on the one HDMI out put.  So, from what you are changing there I should just add the syntax.  Thank you.  Will try that.

Also, would that mean the other port would be 2k or could I force that to be 2k in some way?  And could a 2k and 4k be set up at the same time?  The reason being, IF I could set them up then IF I should want or need to change between 2k LCD and 4k LCD then it would be handy to be able to use the same code and not need to change the config too.  I know I could just "#" out the line each time, but it would be handy to be hot and live.  It would mean that all I needed to do was change the LCD screen as I could leave the board and cables installed ready to go.  A much smaller job.  Your thoughts, please.

I am going to retest the LCD screens and boards today against my laptop.  I have just re-burned the nanoDLP image and done my GCode which works to a terminal/Tv so if the LCDs work then it must be just settings and config


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#7 2020-12-18 10:58:58

Shahin
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Registered: 2016-02-17
Posts: 3,540

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

It is possible but you should check carefully what pi is capable of. I seen too many cases failed because high resolution forced on both output but single output were was working fine.

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#8 2020-12-18 13:06:43

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Thank you.
I shall park that thought for once I have things working - rather optimistic given I have been at this since May and got nowhere and with the amount I have spent on screens and what not I could have bought a new 4k resin printer!

Re this line of code in the config: 

hdmi_timings:0=2160 0 105 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

What is the "24"?  I have several identical settings for "Timings" except for that number...  In some, it is 24, in others 30 and others 60.  I suspected it was the frame rate.  If so then it must have to match this line, "hdmi_enable_4kp60=1" where the 4kp60 is 60Hz, no?

I have tested all the LCDs I have and HDMI boards etc on my laptop and with the above Pi to monitor/Tv working all tests completed.  My only 4k LCD is faulty with the connection slightly split breaking the image - again but does work enough to prove that the other components work and all the 2k components work fine too.  So will focus on 2k for now.  However, suddenly I can not connect to the board, I have no LAN.  The cables are all connected and the LAN works but the Pi Ethernet port is showing a steady orange LED.  So frustrating, so stopping for now.  Had enough.

Last edited by Jonners59 (2020-12-18 13:29:30)


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#9 2020-12-21 06:32:58

Shahin
Administrator
Registered: 2016-02-17
Posts: 3,540

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Yes it is difficult to setup these LCDs, specially as EDID is not available on pi for these. So you need to do all configurations manually.
There is a complete guide on all HDMI parameters on the link below
https://www.raspberrypi.org/documentati … t/video.md

hdmi_timings=<h_active_pixels> <h_sync_polarity> <h_front_porch> <h_sync_pulse> <h_back_porch> <v_active_lines> <v_sync_polarity> <v_front_porch> <v_sync_pulse> <v_back_porch> <v_sync_offset_a> <v_sync_offset_b> <pixel_rep> <frame_rate> <interlaced> <pixel_freq> <aspect_ratio>

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#10 2020-12-21 09:37:03

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Shahin wrote:

Yes it is difficult to setup these LCDs, specially as EDID is not available on pi for these. So you need to do all configurations manually.
There is a complete guide on all HDMI parameters on the link below
https://www.raspberrypi.org/documentati … t/video.md

hdmi_timings=<h_active_pixels> <h_sync_polarity> <h_front_porch> <h_sync_pulse> <h_back_porch> <v_active_lines> <v_sync_polarity> <v_front_porch> <v_sync_pulse> <v_back_porch> <v_sync_offset_a> <v_sync_offset_b> <pixel_rep> <frame_rate> <interlaced> <pixel_freq> <aspect_ratio>

Hiya,
Thank you.  Yes, I have been looking through that, but the important stuff makes no sense to me.  I have learned that I was correct in my assumption, that that entry is the frame rate.  But setting or changing it is not so simple.  Also learned that all the numbers MUST be even as the Pi4 shares across two screen outputs.  So the 105 entry is wrong and will not work.  It has to be changed to 104 or 106...:
2160 0 105 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0
Should be:
2160 0 104 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

Also that the large number at the end is used in this formula to calculate the frequency:
2160 0 104 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

222290000/((2160+0+104+32+100)*(3840+0+12+2+10))=24

What I do NOT know or understand is where these (0, 104, 32, 100, 0, 12, 2, 10, 222290000) numbers come from and what they mean and if I can change any of them to get a reading I want.  Do you know, does anyone know?

Ideally, I would like a 60khz frame rate


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#11 2020-12-21 21:08:03

Shahin
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Registered: 2016-02-17
Posts: 3,540

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

These should come from the manufacturer, some even could change based on clock speed.

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#12 2020-12-21 21:30:33

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

Shahin wrote:

These should come from the manufacturer, some even could change based on clock speed.

OK, but can I change any to get a different output.  I mean I THINK 60Hz is better (don't actually know, just assume) so if I change the pixel_freq to something that gets me a 60Hz using the formula above, does that work?


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#13 2020-12-22 11:14:48

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

I won't lie and say I fully get it, but there is a huge clarity from where I was.  So based on the formula, 222290000 / ((2160+105+32+100) * (3840+12+2+10)) = 24Hz / fps., the ones to test are:

1. Frame Rate 24Khz

2160 0 105 32 100 3840 0 12 2 10 0 0 0 24 0 222290000 0

, changing the 105 to 106 or 104.
Though none of those matches the formula as the "Pix_Freq" does NOT give 24KHz, so it MAYBE and this depends on the answer to the below question, is the formula able to allow the user to gain the correct settings or are they rigidly set by the manufacturer as limitations of the device...  But if the formula is correct and can allow for corrections then this should work with a changed Pix-Freq of 222380928.

2160 0 106 32 100 3840 0 12 2 10 0 0 0 24 0 222380928 0

and

2. Frame Rate 30Khz

2160 0 105 32 100 3840 0 12 2 10 0 0 0 30 0 277976160 0

changing to

2160 0 106 32 100 3840 0 12 2 10 0 0 0 30 0 277976160 0

So, that leaves me with one more question.

1. If I changed the "Pixel Frequency" to 555952320 then it works in the formula to give a 60Hz refresh rate, but can I do this or is this something the manufacturer specifies as a capability of the LCD/HDMI board?  I do not understand the technology that sits behind all this and the values and formula.  However, if I can then the line would be....

2160 0 106 32 100 3840 0 12 2 10 0 0 0 60 0 555952320 0

should that work and give me 60khz?
and this one at 24Khz

2160 0 106 32 100 3840 0 12 2 10 0 0 0 24 0 222380928 0

Your thoughts are very welcome and appreciated.


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#14 2021-01-11 11:43:18

Jonners59
Member
From: London
Registered: 2020-07-07
Posts: 118

Re: Pi4B 4k 5.5" LCD CONFIG - HELP

WORKING!  well, the 4k 2160*3840 LS055D1SX05(G) 5.5" LCD is now working.  This MAY NOT work for all 4K LCDs, check the size and the model number - LSxxxxx

The SSh is not, though not as important as the above, which was the point of the blog.

Solution:
Two files to change in the BOOT directory.
1. Add this

video=HDMI-A-1:2160x3840MR-16@60eD

to the end of the file cmdline.txt

2. config.txt =

#Jonathan's code for a 4k 2160*3840 LS055D1SX05(G) 5.5" LCD
disable_splash=1
boot_delay=0
dtoverlay=pi3-disable-bt
hdmi_ignore_cec_init=1

[pi4]
max_framebuffers=2
framebuffer_priority=2

[all]
hvs_priority=0x32ff
force_turbo=1
gpu_mem=256
enable_uart=1
start_x=0
disable_overscan=1
overscan_top=65
overscan_bottom=10
hdmi_ignore_edid=0xa5000080
hdmi_force_hotplug=1
hdmi_drive=1
hdmi_enable_4kp60=1
hdmi_group=2
hdmi_mode=87
hdmi_pixel_encoding=2
hdmi_pixel_freq_limit=700000000
#hdmi_timings=2160 0 106 32 100 3840 0 12 2 10 0 0 0 24 0 222380928 0
hdmi_timings=2160 0 106 32 100 3840 0 12 2 10 0 0 0 60 0 277976160 3
framebuffer_width=2160
framebuffer_height=3840
framebuffer_depth=16
framebuffer_ignore_alpha=1
max_framebuffer_width=2160
max_framebuffer_height=3840

Hope this saves someone else a lot of time and money - I started in May and have spent nearly £1,000 in LCDs and hardware to get to this point!


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