aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Fri Dec 09, 2016 10:44 am

MichaR wrote:Ah OK, sounds logical to mee. Sure, price is not so importent... also for me as a hobbyist.
Btw.: Do you have any experience with the DS90C387 as LVDS converter?
best regards
Micha
Thinking about higher resolution with dual-pixel LVDS? You may want to get one of these https://www.chalk-elec.com/?page_id=128 ... ry=3094859
So, makes no sense to build this from scratch.

EDIT: DS90C387 is dual-pixel in - dual-pixel out --> will not fit to RPi DPI! That's why TFP401 is used to bridge from HDMI to 48-bit RGB.

For use with RPi 24-bit DPI interface TI's DS90C187 would be the product of my choice (http://www.ti.com/product/DS90C187):
- Single Pixel In, Single Pixel Out (SISO), 105MHz max
- Single Pixel In, Dual Pixel Out (SIDO), 185MHz

Drawback is the package size/type: 7mm x 7mm 92-pin dual row VQFN package --> pain in the butt without access to reflow and SMT placing equipment. I'm still thinking of making a design based on this serializer since it allows for resolutions up to WUXGA+ @60Hz but costs for prototype will be high --> need to consider if it's worth the effort/spending the money.

Maybe I should start a kickstarter campaing for getting rich :lol:

MichaR
Posts: 16
Joined: Thu Mar 10, 2016 5:49 am
Location: Berlin / Germany

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

Fri Dec 09, 2016 12:06 pm

The DS90C387 can also single pixel in to dual pixel out conversion. There is a pin to configure that option (single in/single out, single in/dual out and dual in/dual out). Using an ready solution is not the solution I need. My designs are all based on the compute module done on Eurocard size PCB's for 19 ich rack mount. So I do it byself. I will report, if it works or not.
pain in the butt without access to reflow and SMT placing equipment
Not so easy by hand, but possible... hot air for diepads and the normal solder station for the pins is ok for QFN 8-)

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Fri Dec 09, 2016 12:59 pm

Understood! Did not check the spec in detail. Might be simpler to use this because of package type.

Well, I've hand soldern QFN and VQFN by hand already ... so I know it's possible. If the stencil design is good hoot air is suffienct for the full job.
I'm targeting to have it on a CM baseboard as well. But will wait until I'm able to by a CM3 before starting the design. Will have to finish my backlight driver first since this has to be implememented on the baseboard as well.

Keep us posted on your progress with DS90C387. Don't think you will face issues with this part.

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Fri Dec 09, 2016 1:08 pm

FORGET DS90C187!!! Just had a detailed look at the spec: 1.8Vonly!

MichaR
Posts: 16
Joined: Thu Mar 10, 2016 5:49 am
Location: Berlin / Germany

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

Fri Dec 30, 2016 5:59 am

Hi,

ok I did the test with the DS90C387... works fine for single pixel mode 8-) Have to look for a display with dual pixel interface to test the single to dual pixel conversion mode. Pictures of the board will follow later. The schematic is attached below.

Micha
Attachments
PG08-LVDS-IF.png
PG08-LVDS-IF.png (45.33 KiB) Viewed 4908 times

MichaR
Posts: 16
Joined: Thu Mar 10, 2016 5:49 am
Location: Berlin / Germany

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

Thu Mar 09, 2017 5:59 am

OK, it's late, but I got my PCB's and soldered one partly...

Just a 10x8 cm board for CM1, CM3 and CM3L with the typical ethernet/USB interface, included audio amplifier (not soldered yet), the DS90C387 as DPI to LVDS-converter, backlight controller for smaller displays... all powered by a 12V PSU :-)

Image

Image

Micha

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Thu Mar 09, 2017 6:59 am

Hi Micha,
well done! 4-layers, right? Looking forward to see it in a video!

I'm working on something similar, but different LVDS transmitter (selected one which has switchable mapping, single Pixel in --> single pixel/dual pixel out (selectable via SMD dip-switch)). My power supply circuit will be different as well; will use an 8A 5V DC/DC and a TPS54395 (for 3.3V and 1.8V; supplied by 5V). This will allow me to use (up to) 24V power supplies (btw. 5V DC/DC is rated up to 36V) in case I need to cope with 24V backlights. Remaining difference will be: only USB OTG for me, no Ethernet but WiFi and I will also have HDMI output and a DAC on I2S.
But: still a lot of work to do!
Btw: which PCB CAD tool do you use? I'm using Eagle and made my own CM3 module (SODIMM socket) but ithe layout is not production tested yet :oops: means high risk it's not correct.

Don't let the foundation see the logo on your board :o

MichaR
Posts: 16
Joined: Thu Mar 10, 2016 5:49 am
Location: Berlin / Germany

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

Thu Mar 09, 2017 7:46 am

Hi,
4-layers, right? Looking forward to see it in a video!
yes, 4 layers (top: signal, L2: ground, L3: power, bottom: signal). I will make video later, if I have a full soldered PCB (the audio amplifier is not available at the moment at mouser nor other distributors).
I'm working on something similar, but different LVDS transmitter...
Sounds cool! We are happy to see your progress here.

This board is just a small one to use as a simple mediaplayer with toe option to have network. Additinally an IR-receiver can be connected to control the player. My main work is a bigger board (100x160 mm Eurocard) with PoE class 4 (at) PSU, gigabit network, hardware monitoring (voltage and current), RTC, LVDS and so on to use as servers for rack mount (IP-PBX, ... ). I have the PCBs, but necessary main parts yet (PoE-transformer, network transformer, some power transistors). So that will take even longer. Image from the 3D-simulation (I have no PCB here at the office to take a photo):

Image
which PCB CAD tool do you use? I'm using Eagle
I use Eagle (V7) too - th good old hobby license with max 4 layers and 160x100 routing area. I made my libraries als byself. If you like to compare your SO-DIMM design, just ask by private message. I can share with you of course.
Don't let the foundation see the logo on your board
I think, that should not be a problem. The logo just indicate the place for the compute module and looks identical to the logo on the CM. More critical are the logos on the bottom side. But anyway, it's no comercial product. It's for my private use :-)

Micha

Widz
Posts: 1
Joined: Sun Dec 24, 2017 6:59 am

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

Sun Dec 24, 2017 7:03 am

Hey aBUGSworstnightmare,
Wondering if you still have some of these kicking around? My Nexus seems to have finally kicked the dirt & was hoping to re-purpose the panel!

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Sun Dec 24, 2017 3:31 pm

Hi,
Yes, I still have some of the bare PCBs; you will have to source parts/solder them.
Let me know shipping location and I will figure out postage cost.
MERRY X'MAS

reanonrea
Posts: 2
Joined: Tue Jan 16, 2018 6:10 am

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

Thu Jan 25, 2018 8:18 pm

MichaR wrote:
Fri Dec 30, 2016 5:59 am
Hi,

ok I did the test with the DS90C387... works fine for single pixel mode 8-) Have to look for a display with dual pixel interface to test the single to dual pixel conversion mode. Pictures of the board will follow later. The schematic is attached below.

Micha
Hey. tell me. my project is very similar to yours. I use rpi cm3 and DS90C387. no screen has earned. can a small voltage at the output of the dpi?

reanonrea
Posts: 2
Joined: Tue Jan 16, 2018 6:10 am

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

Fri Jan 26, 2018 7:05 am

MichaR wrote:
Fri Dec 30, 2016 5:59 am
Hi,

ok I did the test with the DS90C387... works fine for single pixel mode 8-) Have to look for a display with dual pixel interface to test the single to dual pixel conversion mode. Pictures of the board will follow later. The schematic is attached below.

Micha
Hi. tell me pliese. my project is very similar to yours. I use rpi cm3 and DS90C387. no screen has earned. can a small voltage at the output of the dpi?

ciconde
Posts: 1
Joined: Mon Feb 12, 2018 6:07 pm

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

Mon Feb 12, 2018 6:12 pm

I'm pretty interested in your add-on

Do you plan to sell it?
I'd be glad using it in a commercial product...

Thanks!
Widz wrote:
Sun Dec 24, 2017 7:03 am
Hey aBUGSworstnightmare,
Wondering if you still have some of these kicking around? My Nexus seems to have finally kicked the dirt & was hoping to re-purpose the panel!

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Tue Feb 13, 2018 9:13 am

ciconde wrote:
Mon Feb 12, 2018 6:12 pm
I'm pretty interested in your add-on

Do you plan to sell it?
I'd be glad using it in a commercial product...

Thanks!
Widz wrote:
Sun Dec 24, 2017 7:03 am
Hey aBUGSworstnightmare,
Wondering if you still have some of these kicking around? My Nexus seems to have finally kicked the dirt & was hoping to re-purpose the panel!
I still have some unpopulated board (bare PCBs) on hands which I'm able to sell at cost.
This board was developed for personel needs so might needs some work in case it's been used in a commercial product.

Send me a PM and let me know your plans so we can discuss possibilities.

oinquer
Posts: 5
Joined: Sat Jun 30, 2012 4:01 pm

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

Tue Mar 06, 2018 3:33 pm

Sorry to necro the post but in all this i have a question,
Is this compatible with a 15.6" inch lvds screen with 6 bit per color (1366x768), i have some background with electronics, but i read LVDS here and then DPI there, so things get confusing....

Thanks

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Tue Mar 06, 2018 6:18 pm

oinquer wrote: Sorry to necro the post but in all this i have a question,
Is this compatible with a 15.6" inch lvds screen with 6 bit per color (1366x768),
yes, it is! Works up to 1366*768pixels at 24-bit colour
oinquer wrote: i have some background with electronics, but i read LVDS here and then DPI there, so things get confusing....
answer is simple : DPI interface is converted to LVDS via a chip from TI. So that's why you read both

oinquer
Posts: 5
Joined: Sat Jun 30, 2012 4:01 pm

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

Tue Mar 06, 2018 7:33 pm

Perfect, will keep the link to comeback later when i need this :D

kevinlieb
Posts: 1
Joined: Thu May 03, 2018 8:29 pm

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

Thu May 03, 2018 8:34 pm

Hello!

I have this display:
http://www.panelook.com/TX31D38VM2BAA_K ... 15426.html
Hitachi TX31D38VM2BAA
1280 x 480
LVDS (1 ch, 6-bit) , Connector , 20 pins

It is almost the perfect size to mount in my VW Bus to replace the glove compartment door ;-)

Can you tell me if this will work with your board?
Can I still buy a complete board from you?

Thanks!!

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Fri May 04, 2018 4:35 am

I don't see any blocking point when looking at the data sheet http://www.avnet-embedded.eu/fileadmin/ ... VM2BAA.pdf

So yes, it's possible from HW POV, but you need to set correct timing details in config.txt

You can use an off-the-shelf cable too.

FUNcation
Posts: 4
Joined: Mon Dec 11, 2017 12:01 am

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

Wed Jul 11, 2018 2:01 am

Hey guys @MichaR, @@aBUGSworstnightmare
is it possible to use one converted board for two LVDS monitors? I want to send same image from Pi3 to two monitors.

Is it possible just to split the cable LVDS or FFC 30P ?

I recently was opening one big monitor and found a 1/2 image splitter card Image but I need something cheap and less complicated. Thanks for any advice

Image Image

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Wed Jul 11, 2018 5:04 am

Hi FUNcation,

let's say your chances might be 50:50. Depends on your display timing and how sensitive the LVDS receiver is in regards of impedance mismatch.
And, as timings for both display will be the same, only works with two identical displays (in case it works at all). Speaking of timing: what resolution do you aim for?

I've never tested this with LVDS but it's working for sure with DPI displays (keep wires short!).

What you can try is using DPI interface and connect it to two LVDS transmitters (one for each display). So your LVDS signals will be according to spec.

Question: which board are you talking about? And, please check your post as (at least I) can't see one of the pictures.

saebinfocus
Posts: 1
Joined: Fri Aug 10, 2018 3:08 pm

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

Fri Aug 10, 2018 4:00 pm

Hello,

i have a question please.
is it possible to use 2 RPi's-zero "parallel" with the LVDS extension?
Another question: The add-on has to be modified so it could fit on a 90*87mm panel used for CubeSATs - could it also be done?
*The reason of using 2 RPi's is to serve several performance purposes.
*LVDS is needed for the Gecko imager:
https://www.cubesatshop.com/wp-content/ ... -11-14.pdf

Thanks in advance for any advice!

Best regards
Saeb

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

Fri Aug 10, 2018 7:22 pm

saebinfocus wrote: Hello,

i have a question please.
is it possible to use 2 RPi's-zero "parallel" with the LVDS extension?
Another question: The add-on has to be modified so it could fit on a 90*87mm panel used for CubeSATs - could it also be done?
*The reason of using 2 RPi's is to serve several performance purposes.
*LVDS is needed for the Gecko imager:
https://www.cubesatshop.com/wp-content/ ... -11-14.pdf

Thanks in advance for any advice!

Best regards
Saeb
this gecko imager is a 'camera', correct? What is the purpose of its LVDS interface? And: what do you want to achieve?

tmanieropiron
Posts: 2
Joined: Wed Nov 07, 2018 1:30 pm

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

Wed Nov 07, 2018 1:43 pm

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

aBUGSworstnightmare
Posts: 1083
Joined: Tue Jun 30, 2015 1:35 pm

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

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.

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