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Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu Nov 08, 2018 11:30 am
by tmanieropiron
write to t.maniero at piron dot it

Thank you!
Thomas

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Mon Feb 25, 2019 10:18 am
by dennisc
Please let me know how to get my email address across to you! Would like to buy one.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Fri Mar 01, 2019 7:14 pm
by aBUGSworstnightmare
dennisc wrote: Please let me know how to get my email address across to you! Would like to buy one.
do it in the same way as Thomas did in the post before yours!

Let me know which display you want to connect (either post.the data sheet or a picture of the LVDS mapping) as I need to check if the remaining boards can be used.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Mon Mar 04, 2019 7:00 pm
by dennisc
here we go!

xxx _at_ me _dot_ com

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 8:03 am
by dennisc
here is the datasheet!
screen2.png
screen2.png (105.22 KiB) Viewed 2628 times

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 9:02 am
by aBUGSworstnightmare
dennisc wrote: here is the datasheet!
Pinout is not what I'm interrested in!
I need to know the LVDS data mapping. So, please check your display spec for some informaton like the one shown below.
R1R0mapping.jpg
Y0= ...R1,R0 LVDs mapping
R1R0mapping.jpg (48.91 KiB) Viewed 2619 times
Your display need to have this mapping as there are no PCBs left which support Y0=..R3,R2 (look at the first post in this treath for seeing the difference).

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 10:01 am
by dennisc
I think it is the right version!
screen3.png
screen3.png (142.54 KiB) Viewed 2610 times

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 10:04 am
by aBUGSworstnightmare
yes, mapping is correct. I will let you know the details by e-mail.

have you received my e-mail btw?

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 10:04 am
by aBUGSworstnightmare
yes, mapping is correct. I will let you know the details by e-mail.

have you received my e-mail btw?

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 10:08 am
by dennisc
Hi,

made a mistake in writing it...

xxxx _at_ me _dot_ com

sorry!

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Tue Mar 05, 2019 10:20 am
by aBUGSworstnightmare
Just send an e-mail to <somebodys mail address > with details.
Let me know if you've received it.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Fri Mar 08, 2019 8:54 am
by aBUGSworstnightmare
Sharp LQ121S1LG81 timing

Code: Select all

#h_active_pixels = 800
#h_sync_polarity = 1
#h_front_porch = 168
#h_sync_pulse = 2
#h_back_porch = 86
#v_active_lines = 600
#v_sync_polarity = 1
#v_front_porch = 43
#v_sync_pulse = 2
#v_back_porch = 21
#v_sync_offset_a = 0
#v_sync_offset_b = 0
#pixel_rep = 0
#frame_rate = 60
#interlaces = 0
#pixel_freq = 40000000
#aspect_ratio = 1
LQ121S1LG81.JPG
Sharp LQ121S1LG81 connected to LVDS4PI
LQ121S1LG81.JPG (129.44 KiB) Viewed 2538 times

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Wed Mar 13, 2019 10:01 pm
by TomekRST
Hi!

Interested in your product. I can’t PM you. Could you send me your email over here: tomtom.mk2 at gmail

Thanks in advance.
Tomek

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu Mar 14, 2019 5:56 am
by aBUGSworstnightmare
TomekRST wrote:
Wed Mar 13, 2019 10:01 pm
Hi!

Interested in your product. I can’t PM you. Could you send me your email over here: tomtom.mk2 at gmail

Thanks in advance.
Tomek
PM function has been disabled on the RPI forum quite a while ago.
Well, I would not call the board 'a product'; it's more a proof-of-concept. Will send e-mail with dot-com domain; let me know in case you did not receive it.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Wed May 22, 2019 8:32 pm
by kelroy
aBUGSworstnightmare wrote:
Thu Mar 14, 2019 5:56 am
TomekRST wrote:
Wed Mar 13, 2019 10:01 pm
Hi!

Interested in your product. I can’t PM you. Could you send me your email over here: tomtom.mk2 at gmail

Thanks in advance.
Tomek
PM function has been disabled on the RPI forum quite a while ago.
Well, I would not call the board 'a product'; it's more a proof-of-concept. Will send e-mail with dot-com domain; let me know in case you did not receive it.
Hi aBUGSworstnightmare, i was reading the whole post and others about dpi to lvds and this inspired me to design one, really thanks to your work man. But i am having a small problem. I really dont know how to obtain the correct dpi_timings and dpi_output_format. Could you help me please?

Or if it's some tutorial/detailed guide to obtain this.

Some photos of my actually job (it's a prototype so i make the things big xD):

Board:
Image
Image


Datasheet:
Image
Image
Image


RGB format, actually i se the jumper to 8.
Image

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu May 23, 2019 6:04 am
by aBUGSworstnightmare
Hi,
Details on DPI are here https://www.raspberrypi.org/documentati ... /README.md

Your display spec should have all the details to figure out dpi_oitput format. You've posted some of the timing details already, polarity infos should be available from some chart in your dieplay spec.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu May 23, 2019 9:34 am
by kelroy
aBUGSworstnightmare wrote:
Thu May 23, 2019 6:04 am
Hi,
Details on DPI are here https://www.raspberrypi.org/documentati ... /README.md

Your display spec should have all the details to figure out dpi_oitput format. You've posted some of the timing details already, polarity infos should be available from some chart in your dieplay spec.
Yes, at least i understand the dpi_output_format.

But on the timmings... i just inderstand a few things like the h and v lanes, frame rate.... but the others, i could not figure how to obtain this in base of the datasheet.

Finally i have it working, damm chinesse datasheets... they are really bad.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu May 23, 2019 1:49 pm
by aBUGSworstnightmare
There should be a chart that explains values from table 3.3.4
There you can see how polarities are etc. And how to interpret the rest

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Fri May 24, 2019 9:36 am
by kelroy
Yes, finally i made it works. At least was hard but i found this post that explain a bit things and with that and other reads i found a solution.

That its the post i saw: https://timetoexplore.net/blog/video-ti ... 720p-1080p

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Wed Aug 14, 2019 12:19 pm
by Raquena
Hello Everybody, and ,pre specifically @MichaR and @@aBUGSworstnightmare,

I'm also interested in building a DPI to LVDS interface for a screen with DUAL LVDS (so I'll be converting 24bit DPI to to SINGLE to DUAL LVDS).
Right now I'm testing the first boards I designed for the specific scree, and as it was expected, it didn't work at the first chance :(
So I'd like to ask you guys, if you could help me a little with the troubleshooting!
Right now, the best I got was:
- green horizontal ribbons.
- red vertical lines.
- not much more... and not for more than 30 seconds.

My current steup is based in MichaR's schematic.

Any ideas of what (or how many things) could generate such state?

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Wed Aug 14, 2019 4:18 pm
by Raquena
aBUGSworstnightmare wrote:
Thu Nov 08, 2018 8:23 am
tmanieropiron wrote: Hi aBUGSworstnightmare,

may I ask if you have two spare lvds boards to sell? I would really like to buy two to play with our lvds displays that currently we are using on another board that have native lvds support.

Thank you,
Thomas
let me know your e-mail address and I can send you the details.
Hello @aBUGSworstnightmare,
I'm trying to send you some private messages regarding to the LVDS interface, but it seems I'm not allowed to do so.
Would be great if you could share with me some of your knowledge regarding to interfacing the raspi with DPI and LVDS.
Thaaaanks!

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu Aug 15, 2019 6:51 am
by aBUGSworstnightmare
Hi,
I know MichaR's schematic and the LVDS transmittter he's using. Make sure it's control signals are correct (data mapping i.e,) for your display. As I'm using a different transmitter on my expansion board for the LVDS4CM3L board (https://www.raspberrypi.org/forums/view ... 0#p1385429) I can't help with debugging your HW.
What about your dpi_timings etc? Is this correct?

https://www.raspberrypi.org/documentati ... /README.md has all the details. You will have to consult your display data sheet for the values.

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu Aug 15, 2019 1:51 pm
by Raquena
aBUGSworstnightmare wrote:
Thu Aug 15, 2019 6:51 am
Hi,
I know MichaR's schematic and the LVDS transmittter he's using. Make sure it's control signals are correct (data mapping i.e,) for your display. As I'm using a different transmitter on my expansion board for the LVDS4CM3L board (https://www.raspberrypi.org/forums/view ... 0#p1385429) I can't help with debugging your HW.
What about your dpi_timings etc? Is this correct?

https://www.raspberrypi.org/documentati ... /README.md has all the details. You will have to consult your display data sheet for the values.
The screen I'm using is WF123BSWAYLNN0
The datasheet that could be found around doesn't contain the timing data, hopefully yesterday I got another datasheet with some more
pages about it :)
I'm not very sure if I'm interpreting the timings completely right though.
Here we go with the timings:
data_format_lcd.jpg
data_format_lcd.jpg (179.66 KiB) Viewed 1234 times
data_format_lcd.jpg
data_format_lcd.jpg (179.66 KiB) Viewed 1234 times
About the configuration, I'm using falling edge clock (that's what I understand from the datasheet).

As far as I('m able to), know the signals are ok:
I'm using a 100MHz Oscilloscope to measure the signals, which seem to be too fast, but at least I know both in the side of the DPI
and in the side of thr LVDS I have signal.

Shouldn't I get at least some random stuff in the screen even if the data format is wrong?
Could it be that I have problems with the power cycle, and that's why I get the scree n displaying stuff only for some seconds?
(indeed, to make it even more strange, the screen shows sth. only after a long time being unpowered, when I power it for the first time).

My mail address is raquena at live dot com, just in case you want to share also some more information per mail

Thank you very much for your help!

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Thu Aug 15, 2019 10:28 pm
by aBUGSworstnightmare
What you've posted here is no timing data! It's the LVDS mapping - which is VESA btw.

You will need to have timing data (see an example here https://www.raspberrypi.org/forums/memb ... e&u=152468) of your screen; without you're screwed up

Re: LVDS add-on for Raspberry models with 40pin GPIO

Posted: Fri Aug 16, 2019 9:03 am
by Raquena
aBUGSworstnightmare wrote:
Thu Aug 15, 2019 10:28 pm
What you've posted here is no timing data! It's the LVDS mapping - which is VESA btw.

You will need to have timing data (see an example here https://www.raspberrypi.org/forums/memb ... e&u=152468) of your screen; without you're screwed up
Hello again,
The link sends me to your profile, so still not sure if this is what you mean, but I think it looks like:
Image

I'm also trying to attach the complete datasheet, but not allowed, because of size reasons.

Anyway, even if the timings are wrong, I should get some random stuff on the screen, right?