How to Connect LCD to LCD expansion header on Rev. C
bobjones
an LCD display is (like maybe PSP screen)?
Gerald Coley
rubik...@googlemail.com
you said all signals are there but my LCD needs:
1 VSS GROUND
2 VSS GROUND
3 VCC +2.5V POWER SOURCE
4 VCC +2.5V POWER SOURCE
5 R0 RED DATA SIGNAL (LSB)
6 R1 RED DATA SIGNAL
7 R2 RED DATA SIGNAL
8 R3 RED DATA SIGNAL
9 R4 RED DATA SIGNAL
10 R5 RED DATA SIGNAL
11 R6 RED DATA SIGNAL
12 R7 RED DATA SIGNAL(MSB)
13 G0 GREEN DATA SIGNAL (LSB)
14 G1 GREEN DATA SIGNAL
15 G2 GREEN DATA SIGNAL
16 G3 GREEN DATA SIGNAL
17 G4 GREEN DATA SIGNAL
18 G5 GREEN DATA SIGNAL
19 G6 GREEN DATA SIGNAL
20 G7 GREEN DATA SIGNAL(MSB)
21 B0 BLUE DATA SINGAL(LSB)
22 B1 BLUE DATA SIGNAL
23 B2 BLUE DATA SIGNAL
24 B3 BLUE DATA SIGNAL
25 B4 BLUE DATA SIGNAL
26 B5 BLUE DATA SIGNAL
27 B6 BLUE DATA SIGNAL
28 B7 BLUE DATA SIGNAL
29 VSS GROUND
30 CK CLOCK SIGNAL TO SAMPLE EACH DATE
31 DISP DISPLAY ON/OFF SINGAL
32 HS HORIZONTAL SYNCHRONIZING SIGNAL
33 VS VERTICAL SYNCHRONIZING SIGNAL
34 NC NC(THIS PIN SHOULD BE FIXED TO GND)
35 AVDD +5V ANALOG POWER SOURCE
36 AVDD +5V ANALOG POWER SOURCE
And on Beagle Rev C. there are:
1 DC_5V PWR DC rail from the Main DC supply
2 DC_5V PWR DC rail from the Main DC supply
3 DVI_DATA1 O LCD Pixel Data bit
4 DVI_DATA0 O LCD Pixel Data bit
5 DVI_DATA31 O LCD Pixel Data bit
6 DVI_DATA2 O LCD Pixel Data bit
7 DVI_DATA5 O LCD Pixel Data bit
8 DVI_DATA4 O LCD Pixel Data bit
9 DVI_DATA12 O LCD Pixel Data bit
10 DVI_DATA10 O LCD Pixel Data bit
11 DVI_DATA23 O LCD Pixel Data bit
12 DVI_DATA14 O LCD Pixel Data bit
13 DVI_DATA19 O LCD Pixel Data bit
14 DVI_DATA22 O LCD Pixel Data bit
15 I2C3_SDA I/O I2C3 Data Line
16 DVI_DATA11 O LCD Pixel Data bit
17 DVI_VSYNC O LCD Vertical Sync Signal
18 DVI_PUP O enabled. Can be used to activate
circuitry on adapter board if
desired.
19 GND PWR Ground bus
20 GND PWR Ground bus
1 3.3V PWR 3.3V reference rail
2 VIO_1V8 PWR 1.8V buffer reference rail.
3 DVI_DATA20 O LCD Pixel Data bit
4 DVI_DATA21 O LCD Pixel Data bit
5 DVI_DATA17 O LCD Pixel Data bit
6 DVI_DATA18 O LCD Pixel Data bit
7 DVI_DATA15 O LCD Pixel Data bit
8 DVI_DATA16 O LCD Pixel Data bit
9 DVI_DATA7 O LCD Pixel Data bit
10 DVI_DATA13 O LCD Pixel Data bit
11 DVI_DATA8 O LCD Pixel Data bit
12 NC No connect
13 DVI_DATA9 LCD Pixel Data bit
14 I2C3_SCL I/O I2C3 Clock Line
15 DVI_DATA6 O LCD Pixel Data bit
16 DVI_CLK+ O DVI Clock
17 DVI_DEN O Data Enable
18 DVI_HSYNC O Horizontal Sync
19 GND PWR Ground bus
20 GND PWR Ground bus
Which LCD Pixel Data bit is the Right Color Bit for my LCD?
On 6 Apr., 02:00, Gerald Coley <ger...@beagleboard.org> wrote:
> You will need to create a buffer card that will translate the levels to
> those that matches the LCD of choice. In addition, the board will need to
> translate the voltages from the 1.8V level to the level as needed for the
> desired display and provide the connector that connects to the LCD panel. A
> PSP LCD can indeed be connected to the expansion header. All of the signals
> are there, you will just need to do the level translation and connector
> matching..
>
> Gerald
>
Hunyue Yau
voltages sure look like it. If so, I can confirm that it definitely are there
and it works.
What you will need to decide first is how do you want to control the LCD and
backlight (enable/disables for both, shared, acceptable interactions with the
DVI output). With pinmux tricks you can recycle some of the lines or give up
a color line or two to use it as a GPIO to control the LCD. Or you can pull
some of the controls off the main expansion header. 24bpp is doable with the
signal but you loose a bit of granularity in the controls as far as being
able to do PM and/or switch with the external DVI signals. Once you have that
figured out then figure out the actual hook up. The allocation of the color
lines are documented in the TRM and will vary depending on how you have
software setup (16bpp/18bpp/24bpp). This setting is seperate from the frame
buffer settings as the DSS can translate to some extent. Main thing is design
how you want to control the LCD before hand.
Btw, do not forget the DVI_PUP signal is at 3.3V. Or there may be some
surprises. ;)
Hunyue Yau
http://www.hy-research.com/
rubik...@googlemail.com
Its an 480x272 PSP-compatible Display!
I'am new to all that linux stuff.
I'am normaly control 4-line Displays with 8bit or 4bit Interface.
Can you give me some detail information on driving this display with
beagle?
I know that i need the right voltages for the LCD.
But where i can see the kernel part where the lcd lines are
configured?
On 4 Mai, 20:51, Hunyue Yau <ybea...@rehut.com> wrote:
> Is this a certain WQVGA screen used in a common hand held toy? The signals and
> voltages sure look like it. If so, I can confirm that it definitely are there
> and it works.
>
> What you will need to decide first is how do you want to control the LCD and
> backlight (enable/disables for both, shared, acceptable interactions with the
> DVI output). With pinmux tricks you can recycle some of the lines or give up
> a color line or two to use it as a GPIO to control the LCD. Or you can pull
> some of the controls off the main expansion header. 24bpp is doable with the
> signal but you loose a bit of granularity in the controls as far as being
> able to do PM and/or switch with the external DVI signals. Once you have that
> figured out then figure out the actual hook up. The allocation of the color
> lines are documented in the TRM and will vary depending on how you have
> software setup (16bpp/18bpp/24bpp). This setting is seperate from the frame
> buffer settings as the DSS can translate to some extent. Main thing is design
> how you want to control the LCD before hand.
>
> Btw, do not forget the DVI_PUP signal is at 3.3V. Or there may be some
> surprises. ;)
>
Gerald Coley
Sean D'Epagnier
>
> Thanks for the fast reply!
> Its an 480x272 PSP-compatible Display!
> I'am new to all that linux stuff.
> I'am normaly control 4-line Displays with 8bit or 4bit Interface.
> Can you give me some detail information on driving this display with
> beagle?
> I know that i need the right voltages for the LCD.
> But where i can see the kernel part where the lcd lines are
> configured?
>
You need to tell the display driver the right clock timings for this
to work. Also note that hsync and vsync are inverted (it took me a
little while to figure this out) I actually edited the kernel source
code to make mine work, but maybe you can do it with a kernel
parameter (the kernel I had didn't support this display yet)
I would be curious to know if the psp display can work at 1.8v..
since it works normally at 2.5v levels it might actually work without
translators (although out of spec)
Sean
rubik...@googlemail.com
I think i'am not the only one who want to use such display.
On 4 Mai, 21:10, Gerald Coley <ger...@beagleboard.org> wrote:
> All signals are there for this display. I just finished designing an adapter
> card for it and it goes into layout later this week.
>
> Gerald
>
Gerald Coley
Sean D'Epagnier
> I have level translators on my board. They are definitely required.
>
Well according to the datasheet, the min Vcc is 2.3, and logic high is
.8*Vcc which would be 1.84. It looks like it wouldn't be quite in
spec, but maybe if you drive it at 2.0-2.3 volts instead of 2.5 then
you could get away without level translators.
Sean
Gerald Coley
Gerald Coley
rubik...@googlemail.com
On 4 Mai, 21:25, Gerald Coley <ger...@beagleboard.org> wrote:
> Keep in mind that there is another devcie already on those signals.
>
> Gerald
>
Gerald Coley
Hunyue Yau
With the current layout, what is a conservative estimate as to the number of
additional pF of drive that is available on the LCD and expansion headers?
Trying to backout how much cabling can be reliably used.
Gerald Coley
atomi...@gmail.com
in hooking one up to the board (maybe the touch screen overlay would
work too?) From what I was reading, I'm guessing that you cant just
hook up the screen to the board and cross your fingers. Sounds like
there is some kernel patching and circuit work to be done.
Gerald Coley
Hunyue Yau
I have the PSP LCD working and I am not happy with it. You can see it on my
website (see .sig). The only thing good about the PSP LCD is that it is cheap
in single quantities other then that, I can't think of anything good to say
about it.
Most of the PSP support stuff is in the latest DSS2 patch already so the
kernel changes are minimal.
The electronics is straight foward; it is a 1 to 1 wiring through a level
converter. About the only thing slightly complex is driving the backlight
unless you want to use a FET and a large stack of batteries to generate the
26V or so for the string of LEDs.
Got a few extra PCBs lying around that I wouldn't mind selling off as I am not
likely to be doing anything more with the LCD. Reply to me directly for
details.
In case anyone else is interested, some of the issues with this LCD is -
it is multivoltage
it requires a tighter tolerance 5Vpower supply then the beagle per the
datasheet. Testing has definitely confirmed the phrase "undefined behavior"
when it is used outside the LCD datasheet range but within the Beagleboard
range
.
Guylhem Aznar
On Thu, May 14, 2009 at 20:27, Hunyue Yau <ybe...@rehut.com> wrote:
> I have the PSP LCD working and I am not happy with it. You can see it on my
> website (see .sig). The only thing good about the PSP LCD is that it is cheap
> in single quantities other then that, I can't think of anything good to say
> about it.
That's the best point, along with its wide availability : COTS
replacement parts are both cheap and easily available, and should
always be preferred.
Which do you tihnk will sell better - $100 kit, LCD included, that
can be plugged to the bb directly, or a $200 kit which requires
specific LCDs that may or may not be available in the future?
So I'd be interested in a board :-)
BTW will displaying on the LCD port disable DVI output, or can both be
achieved (with different res and possibly different framebuffers)
--
Dr. Guylhem Aznar, MD PhD
Unité d'Analyse Médico-Économique
Service de Santé Publique et d'Économie de la Santé
Pôle SPSSR
CHU de Fort de France
BP 632
97261 Fort De France Cedex
Martinique, France
Tel : 05 96 55 23 47
Fax : 05 96 75 84 57
Frantisek Dufka
> I have the PSP LCD working and I am not happy with it. You can see it on my
> website (see .sig). The only thing good about the PSP LCD is that it is cheap
> in single quantities other then that, I can't think of anything good to say
> about it.
What about ipod/iphone displays? They look cheap too. I guess they are
320x480?
http://www.dealextreme.com/details.dx/sku.24897
http://www.dealextreme.com/details.dx/sku.24898
http://www.dealextreme.com/details.dx/sku.24896
Søren Steen Christensen
> 320x480?
>
> http://www.dealextreme.com/details.dx/sku.24897
> http://www.dealextreme.com/details.dx/sku.24898
> http://www.dealextreme.com/details.dx/sku.24896
Does any kind of easy accessible datasheet/information exist for these?
Søren
Vladimir Pantelic
> Hunyue Yau wrote:
>
>> I have the PSP LCD working and I am not happy with it. You can see it on my
>> website (see .sig). The only thing good about the PSP LCD is that it is cheap
>> in single quantities other then that, I can't think of anything good to say
>> about it.
>
> 320x480?
ipod video aka classic is only 320x240.
Dan Poirot
> Hunyue Yau wrote:
>
>> I have the PSP LCD working and I am not happy with it. You can see it on my
>> website (see .sig). The only thing good about the PSP LCD is that it is cheap
>> in single quantities other then that, I can't think of anything good to say
>> about it.
Hunyue Yau
> Hello
>
> On Thu, May 14, 2009 at 20:27, Hunyue Yau <ybe...@rehut.com> wrote:
> > I have the PSP LCD working and I am not happy with it. You can see it on
> > my website (see .sig). The only thing good about the PSP LCD is that it
> > is cheap in single quantities other then that, I can't think of anything
> > good to say about it.
>
> That's the best point, along with its wide availability : COTS
> replacement parts are both cheap and easily available, and should
> always be preferred.
I wouldn't count on long term availability of this particular LCD given that
this is largely sold as a replacement part for a product that is getting old.
One factor that you might not be considering is a system as a whole. I built
the interface for my Beagle MID handheld. For some applications, this LCD may
be just fine. I am not saying it is a bad LCD, my point is that it I am
unhappy with it given my goals. Keep in mind that LCDs run a range of
electrical requirements. One LCD I used before had requirements for things
like a -17V contrast/bias voltage so compared to that, the all positive
voltage requirement is better. This is all relative.
However, given the response, I might reconsider things.
> Which do you tihnk will sell better - $100 kit, LCD included, that
> can be plugged to the bb directly, or a $200 kit which requires
> specific LCDs that may or may not be available in the future?
I'd provide a third choice, a LCD kit that includes the LCD and behaves
better.
>
> So I'd be interested in a board :-)
Will respond off list to keep things O(n)T(opic)for the list.
>
> BTW will displaying on the LCD port disable DVI output, or can both be
> achieved (with different res and possibly different framebuffers)
The signals feeding the LCD connector and the DVI are the exact same signals.
So different res simultaneously is not possible as wired. The TRM alludes to
alternative wiring where the signals can be muxed between multiple LCDs but
things are not wired in a way that the muxing would work.
So, I have made it either LCD or DVI. This is enforced by using the disable
signal for the DVI as the LCD enable signal. Saves a pin and prevents some
confusion in figuring out why a DVI monitor won't work at 480x272. The FB
driver (at least the new one, DSS2) can be setup to let you select which
output in software pretty easily.
Hunyue Yau
datasheet for the Sharp LCD, I would not been able to verify the source of
the problem was the LCD and not an issue elsewhere. LCDs can do weird things
when the specs are exceeded. Like the LCD on the SDP (big OMAP eval board)
appearing washed out but otherwise functional when I gave it a bad refresh
rate due to a silly bug where I used a clock should be a freq instead of a
period or vice versa. Other that it appears to works.
Søren Steen Christensen
> > > http://www.dealextreme.com/details.dx/sku.24898
> > > http://www.dealextreme.com/details.dx/sku.24896
> >
> > Does any kind of easy accessible datasheet/information exist for
> > these?
> > Søren
>
> The lack of data is a big killer for a lot of LCDs. If it wasn't for
> the datasheet for the Sharp LCD, I would not been able to verify the
> source of the problem was the LCD and not an issue elsewhere. LCDs
> can do weird things when the specs are exceeded.
I totally agree, which is why I asked if any public datasheet/specification
for these modules exist. In case not it's really a no go using them
(although they are cheap I admit), unless you want to spend a huge amount of
time reverse engineering the signaling from an original IPod/IPhone, which
though might be possible in case you really want... :-)
/ Søren
Guylhem Aznar
On Mon, May 18, 2009 at 17:44, Hunyue Yau <ybe...@rehut.com> wrote:
> I wouldn't count on long term availability of this particular LCD given that
> this is largely sold as a replacement part for a product that is getting old.
That's the point! The PSP was such a big hit you'll certainly find
spare parts on line for a long long time, at very decent prices. Look
at the gameboy advance.
And unlike brand new LCDs , the specs will match, because they are
sold for replacement!
> However, given the response, I might reconsider things.
It seems to me I am not alone looking for a simple extension board,
with additional UARTs, MMC, LCD, I2C. Ideally it would support a
simple COTS remplacement LCD, but would also feature a LVDS port for
advanced uses.
Maybe you should just ask people what they need, and what would their
pricerange be?
>> Which do you tihnk will sell better - $100 kit, LCD included, that
>> can be plugged to the bb directly, or a $200 kit which requires
>> specific LCDs that may or may not be available in the future?
>
> I'd provide a third choice, a LCD kit that includes the LCD and behaves
> better.
Sure that's better, but the only important things are 1) price 2) availability.
And then again, unless you intend on building thousands per month,
your limit will be LCD. COTS replacement parts are usually a good idea
for any research project.
Søren made a good point with iphone replacement screens. Unfortunately
there are too many different models. That's why I had suggested the
PSP screen. You could also consider the PDAs LCDs (dell, ipaq...) or
the netbooks LCDs - say eeePC 700 replacement screens. You'll
certainly find them for some time too.
A good test is ebay and google: the more sellers, the most available
is the screen. And you can simply indicate to the people purchasing
your board to get them online :-)
> The signals feeding the LCD connector and the DVI are the exact same signals.
> So different res simultaneously is not possible as wired. The TRM alludes to
> alternative wiring where the signals can be muxed between multiple LCDs but
> things are not wired in a way that the muxing would work.
Thanks for your clarification. I hadn't fully understood that.
Robert Kuhn
> The signals feeding the LCD connector and the DVI are the exact same signals.
> So different res simultaneously is not possible as wired. The TRM alludes to
> alternative wiring where the signals can be muxed between multiple LCDs but
> things are not wired in a way that the muxing would work.
So its not possble to use two different DVI monitors with different
resolutions. So to have two displays there is the hdmi port and the
s-video port?!
Robert
Frantisek Dufka
> I totally agree, which is why I asked if any public datasheet/specification
> for these modules exist. In case not it's really a no go using them
Yeah, sorry, for a moment I completely forgot about this bit. I did a
quick google search and the only hint I found was here
http://www.sparkfun.com/commerce/product_info.php?products_id=9188
"Sorry - we don't have any information on the connectors or pinout. You
may want to refer to Apple iPhone hacking website."
So indeed this is a problem. There are some iphone linux websites and
booting video on youtube but I couldn't find any LCD driver source (or
even linux kernel source). And they may just draw into alrady
initialized framebuffer anyway.
Søren Steen Christensen
> resolutions. So to have two displays there is the hdmi port and the
> s-video port?!
Right - One third option is to find a SPI connected display in case only a
low resolution (i.e. 320x240@30fps) 2nd or 3rd display is needed...
/ Søren
Beagle
I'm trying to put this LCD screen with touchscreen on the
BeagleBoard :
http://radiospares-fr.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0476533
I saw in your discussion about how connecting your LCD Screen.
I don't know if connect the LCD Signals (available on the BeagleBoard)
to my LCD Screen will work ( I noticed you are speaking with the
others guys about buffer, level translators...)
I would be happy if you can help me to resolve my issue.
Thanks,
Bastien