LVDS Display

[Michael]

Can I drive a LVDS display directly from the expansion port, or does this require additional hardware?

[George Ioakimedes]

Looks like it can be directly connected to a LVDS panel. I'm not sure of the software control for it but I think I'm going to make an adapter board to test this out if you are interested.

[Bastiaan van den Berg]

On Wed, Dec 19, 2012 at 1:07 AM, George Ioakimedes <georg...@gmail.com> wrote:

Looks like it can be directly connected to a LVDS panel. I'm not sure of the software control for it but I think I'm going to make an adapter board to test this out if you are interested.

I would be :)

--

buZz 

[George Ioakimedes]

OK, I'm think I'm going to make a quick 1st version that routes the LVDS signals to a 40-pin FFC connector which is standard for some of the LVDS panels. That's the problem with LVDS panels, there isn't a standard pinout or connector used. I need to look into power for the LED backlight as most of them require a 12V input so I may need to add a 5V-to12V booster on this adapter board.

I think I'll just bring the other signals out to a 0.100" pitch header so you can have access to the other signals. In order to do this this adapter board will need to be larger than the Cubieboard and will of course sit underneath it.

[Luis Silva]

'm also interested in how this can be done

[George Ioakimedes]

Anyone else interested in this? I'm going to have to add a booster on this board as you'll need 12VDC for the LED backlight on most panels. I might also add a small audio amplifier as well so un-powered speakers can be directly attached.

I've got some projects that this board could work well for but I'm waiting for a reply to let me know when I can buy 10-15 boards for the pilot project.

Trying to buy LVDS cables in low volume can get rather expensive so I think initially I'll design the board to match the connector of something else. That way we can buy the LVDS cable for less than $10 on eBay and it will work. Not exactly what I want to do but it will work for the 1st revision and eliminate 1 unknown variable in the design.

I'm thinking of making the board just a little bit bigger than the Cubieboard and adding 0.100" headers on either side to bring out the unused signals. That should make it easier for anyone to add anything else that they want to.

[Bastiaan van den Berg]

On Sun, Dec 23, 2012 at 3:17 PM, George Ioakimedes <georg...@gmail.com> wrote:

Trying to buy LVDS cables in low volume can get rather expensive so I think initially I'll design the board to match the connector of something else. That way we can buy the LVDS cable for less than $10 on eBay and it will work. Not exactly what I want to do but it will work for the 1st revision and eliminate 1 unknown variable in the design.

I'm thinking of making the board just a little bit bigger than the Cubieboard and adding 0.100" headers on either side to bring out the unused signals. That should make it easier for anyone to add anything else that they want to.

Yes awesome!  So dual functionality, LVDS _and_ general breakout ;)

--

buZz

[George Ioakimedes]

any other interest in a small audio amplifier on this board?

[George Ioakimedes]

Also I see that in the design they have an option to apply power to CON1 which is a 2x2 header but it is under the current DC Jack. The location of CON1 is not detailed in the mechanical drawing either.

I had hoped to add an option power input jack on this baseboard, something like a standard 2.5mm or 2.1mm DC Jack since we'll have room but I think for now we'll have to apply power on the Cubieboard and at least it can feed power to the U14/U15 and I can grab that for the 12V booster.

[George Ioakimedes]

Here's the 1st draft. Just quick and dirty and no board layout yet. Sorry for the cramped schematic sheet but I started by just placing some parts and hoping that it would all fit on 1 page. Most LCDs require a 3.3V power input so I'll have to add that and when I do I'll move all the power to 1 page.

I looked at the Cubieboard schematic and I see that they chose NOT to route out I2S signals which is a shame. Not sure what I'll do about the audio now. TI has some nice combo audio amplifiers with touch controls built-in which might be nice but then we're starting to talk about a much more complicated board layout rather than just a "simple" adapter board.

[George Ioakimedes]

Realized that the A10 has a built-in 4-wire touch screen controller so no need for an external one. If anyone wanted to sue a capacitive touch screen those usually come with USB or serial controllers so no need for anything on this board to support that.

Looks like most 4-wire touch screens use a 4-pin 1.25mm pitch FFC cable so I'll add that and route those signals directly to this connector.

I haven't had time to read but if someone does have time I'm curious how the pin multiplexing works on the A10. Can you selectively assign functions to certain pins or when you select a "mode" (for instance to use the LVDS signals) does that automatically change the function of other pins too?

[killwarez]

Do you have experience of successful connection LCDs to Cubie? I think its the what should think about before making board.

[theRat]

George,

The selection of the multiplexed pin functions is done within the script.bin/fex file.

[George Ioakimedes]

Not to the Cubieboard but to many other boards and processors

[George Ioakimedes]

Do you know if the multiplex function can be enabled on a pin by pin basis?

[theRat]

I believe you can.  Once I get done with xmas I will be spending more time getting the GPIO stuff working for me.  I have successfully enabled an extra uart so far (just the tx/rx and not the cts/rtc as I didn't need those.

[George Ioakimedes]

Ok sounds good. Merry Christmas!

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[theRat]

George,

See this topic.  

https://groups.google.com/d/topic/cubieboard/SPHsSUorvUg/discussion

It tells you how to use gpio pins.  I tried what it suggested and it worked for me.  Read the whole thread.

Hope this helps.

And merry xmas to you also.

[Michal Suchanek]

Hello,

this CubieBase is quite interesting but I have to ask what is the
intended purpose.

Cubieboard has a HDMI connector which would hopefully support standard
DVI screens with standard resolutions as the driver is improved.

As I understand it LVDS is an interface for a laptop screen. Since the
CubieBase will require a particular interface it is unlikely I will be
able to just pull the screen out of an old broken notebook. I can buy
a screen new but it will be usable only with CubieBase and will be
much more expensive than HDMI to DVI cable.

The resulting Cubieboard + CubieBase will likely require a casing to
be usable for anything but testing that a screen can be indeed
attached to Cubieboard. Sure, you can take a wooden box, saw a
rectangle the size of the screen in one side and then put CubieBase on
a piece of log thick enough so it reaches the hole. Maybe you could
even saw just a small hole to pull the display cable through and bolt
the display directly to the side of the box. I would not be excited
about such a device, however. With the added speaker amps you would
get a multimedia kiosk perhaps but who uses that and for what purpose?
I have seen some in the subway and they are made of stainless steel to
last and almost nobody ever uses them.

Thanks

Michal

[George Ioakimedes]

You are correct. Attaching a LCD panel directly to the Cubieboard will not be for everyone. You can purchase many different size LCDs for well under $100 so someone can create their own tablet or small computer for a relatively low cost. My applications are for retail stores, similar to the kiosks you mentioned.

One idea with the audio amplifier is that you could make a small XBMC machine, perhaps for the children's room, that all you need to do is plug in the power and some speakers and you're done.

[theRat]

George,

I asked for an updated drawing with the power pins included.  It has been posted as a dwg on http://dl.cubieboard.org/hardware/  (the v1.1 file).

[George Ioakimedes]

OK, thanks, that looks good, it includes all of the components so other part locations can be checked too!

Now I'm just waiting to hear if the next batch of boards will have a PCB change. I'm hoping that they will and that they will have I2S signals. 

[George Ioakimedes]

Is it possible to generate another mechanical drawing. This drawing has many different layers and I am not able to delete layers or import this into Altium Designer successfully. This drawing has 113 layers in it so perhaps you could export again and not select a layer for each type?

[Tom Cubie]

http://dl.cubieboard.org/hardware/cubieboard_outline_2012-08-08_v1.1.dxf
The dxf file is generated as single layer.

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--
Keep simple, stay foolish.

[George Ioakimedes]

Thanks!

[George Ioakimedes]

I've jumped into the board layout and have some general questions which I've posted over in the Google+ pages. Here's a link to the post, https://plus.google.com/u/0/106001283410043650294/posts/dgGcVMd5YFA

[theRat]

Why does the cubieboard stick out the left when it is 10cm wide?

I would also use the unpopulated CON1 to power the cubieboard (not the pin on U14).  The 5v input there is the same as the on on the barrel connector, while the one is after the diode input protection.  Also the pins on the 2mm headers are only rated to around 1A which explains why the CON1 header has 2 GND pins and 2 5VDC pins.

[theRat]

Mounting holes might also be useful.

On Wednesday, 2 January 2013 10:34:28 UTC+11, George Ioakimedes wrote:

[George Ioakimedes]

Yes, I do plan on using CN1 for power I just haven't decided if I'll add pogo style pins for the contact or go with a 2mm pitch header. I wish CN1 wasn't hidden by the power jack. I don't want to make removal of the the power jack a requirement to using this base board.

I will have mounting holes which line up with the Cubieboard and perhaps more if space permits.

When looking at header costs 50 pin 100mil were common and low cost. I thought the 2extra pins would also be good for power. I think I can shift things a little and make this board the same length as the cubieboard which would be preferred.

[theRat]

I would recommend using a 2mm header for CON1 as anything else will probably be a different height to U14/U15 and cause issues.

I will be making my own baseboard for my cubie at some stage for my own specific purposes so I looked at what was available.  I will be removing the dc connector from my board to allow for the power.  I agree that it would have been better if  CON1 wasn't under it.

[George Ioakimedes]

I still need to look at the spring loaded contacts that Mill Max has and see what current rating they are. Since they're spring loaded you can get away with a different height than U14/U15 (why are headers labeled with a U designator?). If possible I hope to make a combo footprint so that either a 2mm header or the spring pins can be mounted. I might have a project that could use a lot of Cubieboards so the thought of having to desolder the power jack is not appealing.

What other features did your baseboard idea need that I'm not covering? Perhaps I could add them to this board. 

[theRat]

What I need is probably too unique to be a good idea for your board.  Things such as a couple of different rf receivers, a barometrics pressure sensor, SPI(or TWI) IO expenders to drive triacs for solenoid control.  I will design/build my own prototype board at home.

I think my biggest challenge will be getting the alignment of the U14/15 receptacles correct.  I plan on using SMD parts so that I don't have to drill 96 holes (I hate holes).  I think I will reflow the rest of the board and then hand solder the connectors.

[George Ioakimedes]

OK. It does sound like your design needs it's own layout. If you plan on making your own PCB then look at Samtec headers which have alignment pegs, I've used those before and they're great, even in production.

I used to make my own PCBs but gave up several years ago, you just can't beat the cost of places like Seeestudio and my production PCB pricing is even lower than that.

[Yamanoor Sai Ram]

Hi,

Are you designing your own LVDS controller to interface an LCD panel directly to the cubieboard? I am definitely interested to more about this.

At my work, we use off-the-shelf LVDS controllers for LCD panels. I always wondered how LVDS signalling could be programmed.

How is the cubieboard going to control LVDS signalling?

Sai

On Wed, Jan 2, 2013 at 3:47 PM, George Ioakimedes <georg...@gmail.com> wrote:

OK. It does sound like your design needs it's own layout. If you plan on making your own PCB then look at Samtec headers which have alignment pegs, I've used those before and they're great, even in production.

I used to make my own PCBs but gave up several years ago, you just can't beat the cost of places like Seeestudio and my production PCB pricing is even lower than that.

--

[George Ioakimedes]

That's the beauty of some of these new ARM processors (A10, i.MX6) they include a LVDS controller. I too have used separate LVDS boards in the past and even design my own controller board once.

To be honest I'm not a Linux expert so I don't know the details but I do know that the pins can be configured and I assume that you also configure the LVDS output through some user space control.

I guess I should start looking for the details on that since I'm spending time on designing this base board!

[Alejandro Mery]

On 02/01/13 23:12, Yamanoor Sai Ram wrote:
> Hi,
>
> Are you designing your own LVDS controller to interface an LCD panel
> directly to the cubieboard? I am definitely interested to more about this.
>
> At my work, we use off-the-shelf LVDS controllers for LCD panels. I always
> wondered how LVDS signalling could be programmed.
>
> How is the cubieboard going to control LVDS signalling?

the A10 itself cares about that

[Yamanoor Sai Ram]

>>That's the beauty of some of these new ARM processors (A10, i.MX6) they include a LVDS controller.

I am intrigued by this piece of information. Is the base board design going to be open-source? I am interested in connecting a LCD to the cubieboard.

Sai

--

[George Ioakimedes]

I am thinking of making it open source as well as offering it up for sale at a good price. We design and build other boards so it's easy for me to build in production volumes.

I'm working on the audio amplifier portion of the baseboard which I hope to complete tonight. My plan is to order PCBs by the end of this week.

Depending on the community interest I'll decide how many initial PCBs to order. 

[Yamanoor Sai Ram]

Awesome! I'd like to register my interest for one sample

Sai

--

[George Ioakimedes]

OK, I'll keep you posted or you can follow the Google+ Cubieboard Community as I'm posting updates there when time permits

[Giuseppe Tafuro]

I have also interest of one sample.

[George Ioakimedes]

I made a post yesterday about the audio signals on the header (Audio Signal Question). Would someone please check to see if I have a problem with my board or if HPL/HPR are not really routed to the header.

If I can't get audio from the header then my baseboard design progress is stuck.

[George Ioakimedes]

In case you missed my other post, it turned out that my header had some cold solder joints. After reflowing it I was able to get audio signals off of the header. If it wasn't for that problem I might have finished the layout today. I posted an updated rendering over in the G+ community https://plus.google.com/u/0/106001283410043650294/posts/LvAQjDonpn5

[George Ioakimedes]

Updated (and possibly final) schematics and board plots can be found here

[George Ioakimedes]

I've uploaded the BOM spreadsheet at https://docs.google.com/open?id=0B9e70Qli25RGRVYyNXQ0S3poLWs which has costs in it. Without most of the headers the cost is ~$25. I should add in the sockets for the actual Cubieboard since those are of course a requirement.There's a little extra there for ENIG boards which aren't a necessity but the cost adder was only a little more than $1.

If there's enough interest I could probably get these assembled for a total cost of under $30.

My plan is to place the PCB order in ~20 hours from now so let me know if I need to order extras.

[Eddy Belew]

What is "enough" interest in quantity?

Worxx

On 1/5/2013 6:33 PM, George Ioakimedes wrote:

I've uploaded the BOM spreadsheet at https://docs.google.com/open?id=0B9e70Qli25RGRVYyNXQ0S3poLWs which has costs in it. Without most of the headers the cost is ~$25. I should add in the sockets for the actual Cubieboard since those are of course a requirement.There's a little extra there for ENIG boards which aren't a necessity but the cost adder was only a little more than $1.

If there's enough interest I could probably get these assembled for a total cost of under $30.

My plan is to place the PCB order in ~20 hours from now so let me know if I need to order extras. --

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--

[George Ioakimedes]

I don't know the actual assembly cost yet but to hit the $30 mark I think I would have to build at least 100 units. Right now I didn't think there was enough interest to do a campaign like on https://tindie.com/ but maybe there is?

[Yamanoor Sai Ram]

It seems to be similar to Kickstarter. If the fundraiser campaign does not achieve the target, they do not charge the supporters who are interested.

This means the project is either funded entirely or none. I never liked this concept. I think they should still fund the project.

Sai

On Sun, Jan 6, 2013 at 9:49 AM, George Ioakimedes <georg...@gmail.com> wrote:

I don't know the actual assembly cost yet but to hit the $30 mark I think I would have to build at least 100 units. Right now I didn't think there was enough interest to do a campaign like on https://tindie.com/ but maybe there is?

--

[George Ioakimedes]

I am going to order and make 10-15 boards for a project I have. Normally I would order a few prototype PCBs and test it before ordering more but I'm a bit in a time crunch and need to roll the dice. The cost of getting extra PCBs is very small so I'd thought I'd open this up for others.

Perhaps this can be treated as "early adopters" and if more interest happens I can work on a more formal product launch.

[George Ioakimedes]

Does someone have time to research something for me please. It's been on my mind but I haven't had a chance to double check it. Dual Channel LVDS signals are typically labeled ODD and EVEN but the Cubieboard labels them LVDS0 and LVDS1.

I mapped LVDS0 to ODD and LVDS1 to EVEN and I'm not 100% sure that's correct. It would really suck to get this board back and find that I swapped channels! 

[killwarez]

According to several datasheets on ICs, boards and connectors I think that Cubie's LVDS0 = ODD = usual LVDS Channel 1 or Channel A in some docs and LVDS1 = EVEN = LVDS Channel 2 or Channel B. Odd or Even is about channel's number. I guess you're right.

[Yamanoor Sai Ram]

I agree.  This is the explanation they have provided on different datasheets

Sai

--

[George Ioakimedes]

OK, I'm glad at least there was a 2nd set of eyes on that. I'm nervous about not having the actual analog ground on the pin header so I'm adding a 3.5mm jack on the bottom of the board just as a backup plan. The way things are routed I can't put it in a nice place (like on the edge of the board) so it's looking like it will go next to the lower left mounting hole and at a 45 degree angle. Ugly I know but I don't think it's needed and I always like a backup plan.

[George Ioakimedes]

Boards have been ordered. I added a jumper to bridge the output of the 5V switcher to the Vcc-5V pins on the Cubie Header. I also changed the 2x2 power header to allow for either a SMT or TH part to be mounted which gives me the ability to create the exact height I need to use use spring loaded pins to make contact with the optional header under the Cubie power jack.

Hopefully it all works!

[George Ioakimedes]

Is there anyone on this thread that can help with getting LVDS up and running? I'm initially going to test with a 1366x768 15.6" panel. I'd prefer to run a stripped down Linux as my application only needs to play some video files navigated to through a web page perhaps.

 

I can bribe you with a Cubie Baseboard. The PCBs are being produced now and I hope to have them next week.

 

Thanks,

George

[Yamanoor Sai Ram]

Do you need help customizing the Linux build so that it is possible to run some videos on boot? I have some experience in customizing Linux OS but I am not sure I would be able to configure the LVDS channel on the A10. I have no experience but sure can give it a try?

Sai

--

[George Ioakimedes]

Yes, it will be used as a kiosk. I'd like to put the image in NAND well as the user files/videos.

I want to use LVDS for the display, the 4-wire touch screen, and audio from the header which is routed directly to the amplifier on the baseboard.

I've worked with Linux and can do some programming but I'm more comfortable with hardware.

[killwarez]

What kind of help do you need?

To force A10 display picture to LVDS you can make Cubie to operate as tablet. For example here is CM10 for AllWinner A10 and a lot of compatibility files for different tablets. 

Lets take MOMO9 compatibility pack. It contains touchscreen controllers' drivers and script.bin, as you remember script.bin is primary place where we set display output params.

Its my theory :)

[George Ioakimedes]

That's interesting but I know even less about Android based systems. I thought that perhaps the standard Linux HID driver would work for basic touch functions (which is all that is needed, single touch).

[Yamanoor Sai Ram]

I just did a random search for using LVDS controllers with Linux systems. There were examples like:

xrandr --output LVDS --mode 1024x768 --pos 0x0 --output VGA  --mode 1600x1200 --pos 1024x0

I am wondering whether it is so simple to setup the display via LVDS? Are there additional settings to configure the LVDS channel?

Sai

On Wed, Jan 9, 2013 at 4:42 PM, George Ioakimedes <georg...@gmail.com> wrote:

That's interesting but I know even less about Android based systems. I thought that perhaps the standard Linux HID driver would work for basic touch functions (which is all that is needed, single touch).

--

[Ulisses Montenegro]

xrandr uses the X.org support for the RandR protocol, which in turn depends on your display driver:

http://wiki.x.org/wiki/DriverDevelopment#What_about_the_RandR_1.2_modesetting_APIs.3F

I still do not have my Cubieboard, so I cannot say if the current driver supports all the required features, but given the issues with different resolutions/color modes some users have reported, I highly doubt it would be as simple as running xrandr.

--
“If debugging is the process of removing software bugs, then programming must be the process of putting them in.” - Edsger Dijkstra

[jons...@gmail.com]

You need KMS support - Kernel Mode Setting. Has anyone written a KMS
module for this chip yet? It is a big piece of complicated code which
often doesn't get written because vendors won't release enough info
about the video hardware.

That always makes so much sense to me. Keep the programming specs for
the video hardware secret so that no one can write drivers for the
video hardware. And then pay someone under NDA to work on drivers part
time. Of course you end up with lousy video drivers by doing this and
ultimately your CPU chip fails. This has been repeated dozens of
times.

Jon Smirl
jons...@gmail.com

[George Ioakimedes]

OK, now you guys are really making me nervous! I was under the assumption that all you needed to do was to:

• configure the pins to use LVDS
• configure so output is LVDS instead of HDMI
• set the resolution in the bootargs

Who do we need to get involved to make this happen?

[jons...@gmail.com]

You can probably hack together some dedicated code to make the panel
work. Look in the source dumps from the various A10 based tablets.

But a real video driver that is acceptable for kernel submission is
going to have to have all of this support for HDMI, LVDS, CRT, VGA,
etc all handled in a unified KMS video driver. It also needs to
support EDID and automatically setting the resolution, timing, etc.
Plus that driver needs to do the memory management for the 3D
hardware. There is a lot of software work needed to fully bring up
the video hardware.

All of this is complicated since at some point you are going to want
hardware video acceleration to work.

[Bastiaan van den Berg]

LVDS _is_ working in the current driver, don't listen to all this
negative talk ;)

There are Allwinner A10 tablets being sold that use the LVDS with this
current driver. Just look in their fex code etc, should just be a
matter of configuration.

xrandr, KMS, all that, yes very nice. Not supported by the driver we
have and the one that is working.
Also absolutely not needed for LVDS output.

--
buZz

[George Ioakimedes]

My thought were that since there are many tablets based on the A10 that LVDS support would be available. Many of the 7' screens could be TTL but the ~10" should be LVDS. I'm not a Lunix Guru so I was really hoping that this forum would help put something together for the Cubieboard.

[Bastiaan van den Berg]

On Thu, Jan 10, 2013 at 6:19 PM, George Ioakimedes <georg...@gmail.com> wrote:
> I'm not a Lunix Guru so I was really hoping that this forum
> would help put something together for the Cubieboard.

Sure. send me a LVDS module and a way to hook it up to cubieboard and
I could take a swing at it ;)

--
buZz

[flo....@gmail.com]

Hi @all!

My name is Florian, I'm a Mechatronics student from Austria.  I have been planning to DIY my own set of lab equipment (similar to c't lab).
Cubieboard is my choice for the crux of my lab-PC, as it offers anything I need (GPIO, I2C/TWI, UART, USB, LVDS).
(OT: I could not find a vendor for Austria, until now. Could *anyone* point me to a cost effective, non-credit card order??
I would HIGHLY appreciate any advice, thanks in advance)

Eventually: I'm going to connect some old LCD to my cubie, via LVDS. (Easily integrable solution)
Therefore I am highly interested in this topic, and will try to contribute.

Best regards, Florian

[George Ioakimedes]

buZz: We'll see what happens here but once I get the baseboard built (hopefully next week) the hardware portion should be easy.

--
buZz

[Craig Hastie]

PayPal is available in the shop now, that should allow to purchase without credit card.
Craig

--

[Giuseppe Tafuro]

I agree with Bastiaan,

 

Dont listen to all this negative Talk.

 

Am Donnerstag, 10. Januar 2013 17:15:27 UTC+1 schrieb Bastiaan van den Berg:

[George Ioakimedes]

Should I/we start a new thread that is dedicated to bringing up a board with LVDS output? It should probably go on a Wiki. I started playing with creating an image yesterday but I'm just stumbling around a bit now since I'm not a Linux Guru

[Giuseppe Tafuro]

I think it make sense to go on a Wiki.

What cubieboard do you have 512MB or 1GB? What panel do you want to use?

[George Ioakimedes]

You know I'm embarrassed to say I don't know which version I have, it came from the Indigo campaign. I've only booted it enough to do my initial testing.

--

[theRat]

Indiegogo provided 1GB boards.

[Rolando Quivira]

Hi all =)

First of all, I succedded to turn on a LCD display trough LVDS. I think no one has posted some results... so.. heres my grain of sand.

Here's some images of it:

I started to look for LVDS for the cubie because a LCD came to me and searching the datasheet..... I FOUND IT... yes, I was really surprised because I have never been able to find a datasheet of the LCD's that comes to my hands... this was the first one.

Then I started to make a little pcb for test it and when I was searching for documentation I found this thread and I followed it (not to often).

Ok.. so...  I'm going to organize all of my stuffs that I've done so far to put it on this thread... I'm going to put the test pcb too so be patient, please. Tomorrow I think I'll be able to put the steps.

I do not have much experience with Linux, I'm an Electronic engineer, and in my free time I play with these boards. In fact this is the first time I do something in one of them worth to mention. i think. As I'm all hardware I'm trying to understand linux from the inside... yes... I don't know anything of it.. I know... but I have an urge to know how it does what it does, I just can't live on the higher levels of abstraction and feel happy, there's allways something that pulls me down.

If I'm missing something or if the thread is somewhere else let me know, maybe I'm just wasting your time.

Well it's the first time I post something to collaborate/help others on the web, not because I'm selfish... it's just because I'm very lazy hehe... 

[George Ioakimedes]

Rolando:

Great work! I was waiting to test LVDS until after everything else was done with my baseboard. I am very curious to know what you did in order to enable the LVDS display. Could you at least for now share your FEX settings and what LCD panel you are using.

I would really appreciate it!

Best Regards,

George

[Windsor Schmidt]

George, I'd like to register my interested in buying a board. I have a 22" LVDS panel pulled from an HP Touchscreen PC that I'd like to use with a cubieboard (I don't have a cubieboard yet, hopefully soon).

Cheers,

-Windsor

On Saturday, December 1, 2012 2:33:19 PM UTC-8, Michael wrote:

Can I drive a LVDS display directly from the expansion port, or does this require additional hardware?

[Rolando Quivira]

Thanks George...

I can't attach the fex.... here's the LCD part of it the other part is the same as the git repository

----------------------------------------

....

[disp_init]

disp_init_enable = 1

disp_mode = 0

screen0_output_type = 1

screen0_output_mode = 4

screen1_output_type = 1

screen1_output_mode = 4

fb0_framebuffer_num = 2

fb0_format = 10

fb0_pixel_sequence = 0

fb0_scaler_mode_enable = 0

fb1_framebuffer_num = 2

fb1_format = 10

fb1_pixel_sequence = 0

fb1_scaler_mode_enable = 0

lcd0_bright = 197

lcd1_bright = 197

lcd0_screen_bright = 50

lcd0_screen_contrast = 50

lcd0_screen_saturation = 57

lcd0_screen_hue = 50

lcd1_screen_bright = 50

lcd1_screen_contrast = 50

lcd1_screen_saturation = 57

lcd1_screen_hue = 50

[lcd0_para]

lcd_used = 1

lcd_x = 1024

lcd_y = 768

lcd_dclk_freq = 65

lcd_pwm_not_used = 0

lcd_pwm_ch = 0

lcd_pwm_freq = 10000

lcd_pwm_pol = 0

lcd_if = 3

lcd_hbp = 320

lcd_ht = 1348

lcd_vbp = 38

lcd_vt = 1616

lcd_hv_if = 0

lcd_hv_smode = 0

lcd_hv_s888_if = 0

lcd_hv_syuv_if = 0

lcd_hv_vspw = 0

lcd_hv_hspw = 0

lcd_lvds_ch = 0

lcd_lvds_mode = 0

lcd_lvds_bitwidth = 1

lcd_lvds_io_cross = 0

lcd_cpu_if = 0

lcd_frm = 1

.....

----------------------------------------

The lcd that I'm using is the lp150x08-a2 ( search in google  "filetype:pdf lp150x08", it's the first pdf)  so you can compare.

And here is the test commands ("boot the kernel" part):

http://rhombus-tech.net/allwinner_a10/Compile_X11_driver_for_A10/

Bye =)

[George Ioakimedes]

Thanks!! I'll try to do some testing this weekend. So it looks like you didn't have to worry about details of the signal (like front porch, back porch, etc.)?

How can this setting work if this value:

lcd_lvds_ch = 0

But the LP150X08 panel is a single channel LVDS type?

I think some information about how the FEX files really work is hidden from us!

Best Regards,

George

--

[George Ioakimedes]

Hi Windsor:

OK! I am currently trying to get VGA up and running (there is a discussion about it in another thread). Once I get that working I'd like to test LVDS and it looks like Rolando has already helped with that so if I'm lucky I can get both VGA and LVDS working with notes on what is needed to do since that seems to be the hardest part!

Best Regards,

George

--

[Rolando Quivira]

Hummm I think it's ok:

;lcd_lvds_ch:     0:single channel; 1:dual channel

Here's the 2 links for the FEX.

https://www.google.cl/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDEQFjAA&url=http%3A%2F%2Fwww.henriknordstrom.net%2Fcode%2FA10%2Fdoc%2FCrane_Fex_Guide%2520v0.4%2520%25EF%25BC%2588EN).pdf&ei=nEkDUYuIDYSi8gTD84GgDg&usg=AFQjCNG2ZkArt_e3XkUue1IRfSzG5u8dqw&bvm=bv.41524429,d.eWU

http://linux-sunxi.org/Fex_Guide

=) 

[George Ioakimedes]

My apologies, I forgot to check and just saw 0 and assumed it meant OFF. I've been looking at too many documents lately and my head hurts!

Can you share the image you are booting?

[Rolando Quivira]

I get error #340 attaching files... =S but... I compiled the u-boot & kernel from the linux-sunxi and the rootfs I took it from linaro's images (alip), here's the link of the fs (just the fs):

http://releases.linaro.org/12.11/ubuntu/precise-images/alip

Take the last one... the "heaviest" one.

Other thing... I think I've dealed with the porchs but not too much.. I've just put the parameters of the datasheet (page 26) into the fex:

lcd_hbp = 320   <--- this one (horizontal blanking)

lcd_ht = 1348

lcd_vbp = 38    <--- and this one. (vertical blanking)

lcd_vt = 1616

vt & ht are simply this (I get this in the errors at load the lcd module on linux):

lcd_ht >= (lcd_hbp+lcd_x*1+4)

(lcd_vt/2) >= (lcd_vbp+lcd_y+2)

Bye.

[George Ioakimedes]

I created a cubie FTP account on my server if you want to upload there. the account information is:

Server:  iotllc.com

name:  cubie

pswd:   i will PM you so it is not listed publicly

--

[Rolando Quivira]

First of all.

I don't want to start from the beginining since maybe many of you have done several things, and the only thing that you need to do is fixing the fex to make it work. Anyway, I'm going to put every step because many times I got in situations like "you need to patch with the thing you like"... and I have to stumble in other pages to find how I can do that since I got there with no previous knoledge. Maybe I clean it later to put links instead of the full work/story.

I'm not putting the u-Boot and SDcard part, but If you want I can post it later.

-----------------------------------

Let's get started!:

Editing the fex.

(usefull link: Fex guide)

(usefull pdf:  Crane_FEX_guide v4.0)

- First you need to download the original fex that you're going to edit. These original fex are in the git repository of the linux-sunxi repo ( Linux-Sunxi ) beneath the sunxi_boards/sys_config/a10/. Here you have multiple fex files for different boards. For this case I need the cubieboard.fex since I have the 1G version of the cubieboard.

# wget https://raw.github.com/linux-sunxi/sunxi-boards/master/sys_config/a10/cubieboard.fex

Once you get the file and opened it you need to edit some entries on this two sections: [disp_init] and [lcd0_para], but what to edit? you need to know your lcd pannel now. In my case I have the lp150x08 lcd pannel, its datasheet is here (for reference): LP150X08-TLC1 datasheet

As you can see this pannel has a resolution of 1024x768@60Hz, LVDS interface, 18bits, etc, etc.

In the [disp_init] of the fex the only line that you're going to edit is "screen0_output_type" from 3(hdmi) to 1(lcd):

screen0_output_type = 1

 

And in the [lcd0_para] the ones acording to your lcd. In my case the parameters I have to set are on the page 26 of the lcd datasheet listed above. Heres the resulting values (only the changed lines):

lcd_x = 1024
lcd_y = 768
lcd_dclk_freq = 65

lcd_if = 3                ; (3 = LVDS)
lcd_hbp = 320

lcd_ht = 1348
lcd_vbp = 38

lcd_vt = 1616
lcd_lvds_bitwidth = 1     ; (1 = 18 bits)
lcd_frm = 1               ; (dither 1 = RGB666)

lcd_ht and lcd_vt are just calculations. I get this formulas in the errors i got in my previous tests:

lcd_ht >= (lcd_hbp+lcd_x*1+4)
(lcd_vt/2) >= (lcd_vbp+lcd_y+2)

So, after we have changed the fex fitting our needs we need to create the script.bin from it. For this we need to get the sunxi-tools and compile them:

$ git clone git://github.com/linux-sunxi/sunxi-tools.git
$ cd sunxi-tools/
$ make

copy the modified .fex (cubieboard.fex in this example) to sunxi-tools/ and run:

$ ./fex2bin cubieboard.fex script.bin

now you have to copy the "script.bin" file to your fat partition of the sd card and you're ready to go!.

Note: The version of the u-boot that I have work with the default enviromental variables so in my sd fat partition I only have the script.bin and the uImage.

Testing the LCD

After you put your sd card on the cubieboard and started linux follow teh instructions on the "Boot the kernel" part of this page:

Compile_X11_driver_for_A10

In my case I just needed to put "modprobe lcd" to see the boot msgs in my lcd (on the picture of my first post here)

Compiling the Kernel

(link used: First Steps)

If you don't have any uImage or when you run modprobe you get errors or module not found, etc, etc you probably need to compile the kernel and the modules

To do this you need:

- build essentials

$ sudo apt-get install build-essential

- the arm toolchain 

$ sudo apt-get install gcc-arm-linux-gnueabihf

- To make the uImage you'll need:

$ sudo apt-get install u-boot-tools

(or sudo apt-get install uboot-mkimage.. I don't remmember if you compile and do not get an uImage file isntall this)

- others that I think I've used... but not sure

$ sudo apt-get install libusb-1.0-0-dev

If I'm missing something it's because I don't remember or it was installed on my linux before, but don't worry, the two tools you'll need are:

- sudo apt-cache search word-to-search-or-lib-etc

- google.

Now you need to run this in the folder of your choice (I was on the Desktop, don't worry, it will create a separate folder so you don't worry for the mess)

$ git clone git://github.com/linux-sunxi/linux-sunxi.git
$ cd linux-sunxi
$ git checkout sunxi-3.0
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- sun4i_defconfig
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j5 uImage modules

and now just to put everything in one folder:

$ mkdir output
$ cp arch/arm/boot/uImage output/
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_MOD_PATH=output/ modules_install

Done! now you have your kernel and modules.

Put the "uImage" in the fat partition next to the script.bin and the "lib" folder on your rootfs. If you see the /lib/modules/ was empty and now you have a 3.0.57+/ on it.

If you don't have a rootfs on your ext partition I would recommend the linaro alip form this page as this is the one I've used. 

Linaro Releases

Take the last one... the "heaviest" one. Untar it and put the contents of the folder "binary/boot/filesystem.dir/" inside your ext partition (you need to be root for this) and don't forget to add the "lib" folder on it (the one that is in the "output" folder when we compiled the kernel)

----------------------------

Later I'm going to test some others FS and test the kernel 3.4 too, maybe with a desktop image woud start right into X without any intervention.

As I said In the beggining I've done this "tutorial" for those who want all the info in one page and for my own reference too (I have a very bad memory) I know it has too much repetitive content from other pages.

I'm sorry if you find this post excesive.

Bye!, I hope this could be usefull to many people.

[Rolando Quivira]

Hi again.

George I've tested the rootfs image: linaro-precise-ubuntu-desktop-20121124-560.tar from:

Ubuntu desktop

And worked =): Image:

Does any1 know how to make teh script.bin work with the android that comes in the board? where to redirect the boot?

Bye =)

[georg...@gmail.com]

Thank you very much for detailing the steps you took to get LVDS working for you. I have one quick question, do you also have HDMI working at the same time as LVDS or have you tried this?

[Rolando Quivira]

No, At first I was booting with 2 screens&same fb, but it didn't work The parameters when I load the module gave me errorrs and they were all '0' (lcd_x = 0, etc). When I put only the lcd It worked.

Later I'm goig to keep testing.

[Davn]

Hi!

Prompt connection diagram PIN PDx for LVDS LP150X08, resistors required?

[Rolando Quivira]

Hi Davn

Well.. if you're asking if I put some resistor in the LVDS connection then no, The only thing I did is connecting the pins to the lcd and powered it with a 3,3v ldo reg.

On the BL control I've putted some resistors but they are only pull ups to 3,3v to enable the inverter (I did this to simplify the test board). So they are not controlled by the cubieboard. George says that the BL controls worked fine on his lcd. Check his image on the "Cubie Baseboard" thread.

B.R.

[Davn]

Thanks, but I meant the channel LVDS.

Please tell me how to connect cubieboard, LCD panel. Which outputs to use for data transfer?

пятница, 1 февраля 2013 г., 20:05:16 UTC+6 пользователь Rolando Quivira написал:

[George Ioakimedes]

Maybe my baseboard would be helpful for you to connect your panel?

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[Davn]

Thank you, your baseboard is useful, but I need to do it without her.

суббота, 2 февраля 2013 г., 2:51:01 UTC+6 пользователь George Ioakimedes написал:

[Rolando Quivira]

Well... 

For the data transfer you need to use the LVDS pins, of course... I know it's obvious... but.. since you're asking.

Look here for the pins:

Expansion ports

If you have the same lcd that mine the pins you'll need are: 1, 3, 4, 5, 6, 7, 8, 10 (lvds signals) of the U14 Expansion port.

And obviously you have to power the lcd with 3,3v. And +GND (pin 2 of the U14 expansion port)

Bye.

[Giuseppe Tafuro]

Hi all,

I was able to adapting a NEC SVAXG10TB panel to work with the cubieboard. Basically I 

follow the instruction posted by Rolando for the fex file (thanks for the manual). I used berryboot to install Linaro and

modify the fex file. The Compile_X11_driver_for_A10 step wasn't needed.

George when will be your board available?

 

[George Ioakimedes]

Baseboard is shipping this week. Details very very soon...

Good work!

[Rolando Quivira]

Nice work Giuseppe, congratulations =)

One question: did you modify the fex for the berryboot before or after the os download? the first time I modified the fex for the berryboot it doesn't showed any OS, so I put the original back and it worked again, I must say that it was the only test that I did and it was the first fex that I changed, so... maybe I did something wrong. 

Oh, and we are all especting the baseboard to be ready hehe.

Bye!.

[Giuseppe Tafuro]

Hi Rolando,

 

I install the OS first using an external Display over HDMI. After that I convert the original script.bin to fex, modify the fex and convert back to bin.

 

The next step is to modify the fex so that it will support an external Display in clone mode or extended mode, I hope by this weekend.

[Michal Suchanek]

Hello,

On 19 December 2012 02:59, George Ioakimedes <georg...@gmail.com> wrote:
> OK, I'm think I'm going to make a quick 1st version that routes the LVDS
> signals to a 40-pin FFC connector which is standard for some of the LVDS
> panels. That's the problem with LVDS panels, there isn't a standard pinout
> or connector used. I need to look into power for the LED backlight as most
> of them require a 12V input so I may need to add a 5V-to12V booster on this
> adapter board.
>
> I think I'll just bring the other signals out to a 0.100" pitch header so
> you can have access to the other signals. In order to do this this adapter
> board will need to be larger than the Cubieboard and will of course sit
> underneath it.


I tried to rip a LVDS from an old notebook. It says it is IAXG02C on
the panel and the datasheet says that it has HIROSE DF19L-20P-1H
connector which sounds reasonable. This is wired with actual wires to
an unknown 2-row female connector which connects to the laptop
mainboard. Since this tends to be the standard way to connect a LVDS
in a laptop it is not going to work with the baseboard I guess. I
think the reason is flat cable would break from bending in the display
hinge.

Any idea how hard it would be to find the cable for connecting such display?

I can find the connector on online sites but shipping costs from most
would be terrible.

Thanks

Michal