FACE module hardware design questions (LVDS, eDP and others)

sonnenfl
Posts: 10
Joined: Thu Oct 11, 2012 11:48 am

FACE module hardware design questions (LVDS, eDP and others)

Post by sonnenfl »

Hello,
I have a few questions regarding FACE module hardware design for the IntensePC:

LVDS signals missing in FACE module design guide
As seen here LVDS signals from the graphics chipset are available to FACE modules.
The FACE module design guide doesn't mention LVDS at all.
I found some infos in the FACE module design package (in the schematic of the LAN FACE module).
Can someone please update the design guide to include information about the LVDS pins?


Embedded DisplayPort
Is there a "embedded DisplayPort" on the same pins as LVDS?
If so, how can I make sure that I get LVDS and NOT eDP signals on those pins?
I'm asking this question because in the LAN FACE module schematics every LVDS pin of the connector has "eDP" as alternate function: "LVDS_A0+/eDP_TX0+", "LVDS_A0-/eDP_TX0-", ...


LVDS = FPD-Link (?)
I've read on Wikipedia that the term LVDS is very often misused as a synonym for FPD-Link although LVDS is just a technique for transmitting bits with high speeds without any protocol.
I've checked an Intel application note that gives some information about their LVDS signals and compared that to a FPD-Link driver datasheet and found that the bit protocol is the same.
Can somebody confirm that the LVDS signals are actually FPD-Link signals?


LVDS also on FitPC3?
Are there pins on the FACE module connector of the FitPC3 that output LVDS or is this feature exclusive to the IntensePC?
If there are no LVDS signals on the FPC3: Is there a way for FACE modules to detect if they are built into a FitPC3 or a IntensePC?


FACE module mechanical specifications are missing measures
The FACE module mechanical specifications (PDF file) are missing very essential measures, like the positions of the connectors and some others.


Extra space for FACE modules
I noticed that there is actually 5 mm extra space on both sides of FACE modules (at least in an IntensePC).
Is there a reason why FACE modules aren't allowed to use that space?


6 pos connector near FACE modules
I've noticed the 6 position connector on the main board that links to the small LED board with the IntensePC logo.
Is there a pinout available for this connector?
Can those signals also be found on the FACE module connector?


Detection of ACPI S3 power state ("standby")
Can this power state be detected by a FACE module?


Thanks in advance!

-- Florian

gabrielh
Site Admin
Posts: 1260
Joined: Thu Jun 02, 2011 1:13 pm

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by gabrielh »

Embedded DisplayPort
Is there a "embedded DisplayPort" on the same pins as LVDS?
If so, how can I make sure that I get LVDS and NOT eDP signals on those pins?
I'm asking this question because in the LAN FACE module schematics every LVDS pin of the connector has "eDP" as alternate function: "LVDS_A0+/eDP_TX0+", "LVDS_A0-/eDP_TX0-", ...

Answer: No, there is only an LVDS signals


LVDS = FPD-Link (?)
I've read on Wikipedia that the term LVDS is very often misused as a synonym for FPD-Link although LVDS is just a technique for transmitting bits with high speeds without any protocol.
I've checked an Intel application note that gives some information about their LVDS signals and compared that to a FPD-Link driver datasheet and found that the bit protocol is the same.
Can somebody confirm that the LVDS signals are actually FPD-Link signals?

Answer: Yes LVDS mean FPD-Link but pay attention many displays have a little offset from the standard


LVDS also on FitPC3?
Are there pins on the FACE module connector of the FitPC3 that output LVDS or is this feature exclusive to the IntensePC?
If there are no LVDS signals on the FPC3: Is there a way for FACE modules to detect if they are built into a FitPC3 or a IntensePC?

Answer: No, FIT-PC3 has no lvds pins at external connector (FACE module conn.) BIOS can detect the FACE module and an SBC by read their information from I2C EEPROM.


FACE module mechanical specifications are missing measures
The FACE module mechanical specifications (PDF file) are missing very essential measures, like the positions of the connectors and some others.

Answer: Please be more specific


Extra space for FACE specific
I noticed that there is actually 5 mm extra space on both sides of FACE modules (at least in an IntensePC).
Is there a reason why FACE modules aren't allowed to use that space?

Answer: Please be more concrete


6 pos connector near FACE modules
I've noticed the 6 position connector on the main board that links to the small LED board with the IntensePC logo.
Is there a pinout available for this connector?
Can those signals also be found on the FACE module connector?

Answer: Yes, in IntensePC BOARD_LED# and SATA_LED# (LED signal) are available on a FACE module.


Detection of ACPI S3 power state ("standby")
Can this power state be detected by a FACE module?

Answer: Yes, in a FACE module sleep signal is available.
Gabriel Heifets

Fit-PC2/3/IntensePC support.

sonnenfl
Posts: 10
Joined: Thu Oct 11, 2012 11:48 am

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by sonnenfl »

gabrielh wrote: LVDS also on FitPC3?
Are there pins on the FACE module connector of the FitPC3 that output LVDS or is this feature exclusive to the IntensePC?
If there are no LVDS signals on the FPC3: Is there a way for FACE modules to detect if they are built into a FitPC3 or a IntensePC?

Answer: No, FIT-PC3 has no lvds pins at external connector (FACE module conn.) BIOS can detect the FACE module and an SBC by read their information from I2C EEPROM.
I meant it the other way around: I want to make a FACE module with a microcontroller on it.
The microcontroller should find out if the FACE module it sits on is built into an Fit-PC3 or Intense-PC.
So for example if there are differences in the connectors for Fit-PC3 FACE modules and Intense-PC FACE modules that can be easily detected (for example a pin that is GND in the old one and 5V in the new one) that would be great to know.
The only thing I found is a COM port on EXT2 at B29...B37 that was "RESERVED" before.
gabrielh wrote: FACE module mechanical specifications are missing measures
The FACE module mechanical specifications (PDF file) are missing very essential measures, like the positions of the connectors and some others.

Answer: Please be more specific
Sure, in the top view the following dimensions are missing:
  • Position of the two 100-pos connectors. Preferably given by the position of the drilling holes.
  • Position of all 3 mounting holes.
  • The cutouts on all 4 corners are missing their height and width and (only the ones at the top) the curve radius.
  • The dimension arrow head on the upper left side doesn't end at the top of the board but at the top of the equippable space. So adding the vertical dimensions together will get you 49.35mm instead of the correct 49.85mm.
The bottom view has similar problems but it might be a bit difficult to dimension it.
gabrielh wrote: Extra space for FACE specific
I noticed that there is actually 5 mm extra space on both sides of FACE modules (at least in an IntensePC).
Is there a reason why FACE modules aren't allowed to use that space?

Answer: Please be more concrete
Sure, here is a photo of a 4xUSB FACE module in the bottom part of the Intense-PC:
Image
I've drawn circles to show the 5mm on both sides that could in theory be used by a FACE module.
Is there some reason why the official documentation specifies the module to be smaller than possible?
gabrielh wrote: Detection of ACPI S3 power state ("standby")
Can this power state be detected by a FACE module?

Answer: Yes, in a FACE module sleep signal is available.
Thanks, I found it: SLP_S3#.
I thought it was used as input so that a FACE module can send a sleep request to the OS.
Instead it is an output signal.

On page 15 of the "FACE module design guide" I found the following text:
"SLP_S3# signal may be utilized to implement power supply control. Please note SLP_S3# polarity requirements."
What are these polarity requirements? I couldn't find them in the document.


Thank you for your answers.

-- Florian

igor
Posts: 44
Joined: Wed Nov 09, 2011 1:25 pm

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by igor »

sonnenfl wrote:gabrielh wrote:
LVDS also on FitPC3?
Are there pins on the FACE module connector of the FitPC3 that output LVDS or is this feature exclusive to the IntensePC?
If there are no LVDS signals on the FPC3: Is there a way for FACE modules to detect if they are built into a FitPC3 or a IntensePC?
Answer: No, FIT-PC3 has no lvds pins at external connector (FACE module conn.) BIOS can detect the FACE module and an SBC by read their information from I2C EEPROM.

I meant it the other way around: I want to make a FACE module with a microcontroller on it.
The microcontroller should find out if the FACE module it sits on is built into an Fit-PC3 or Intense-PC.
So for example if there are differences in the connectors for Fit-PC3 FACE modules and Intense-PC FACE modules that can be easily detected (for example a pin that is GND in the old one and 5V in the new one) that would be great to know.
The only thing I found is a COM port on EXT2 at B29...B37 that was "RESERVED" before.
Unfortunately there are no pins that were specifically dedicated for that purpose. I'll ask engineering to check if any pins can be used for that and update you if they find anything suitable.
sonnenfl wrote:gabrielh wrote:
FACE module mechanical specifications are missing measures
The FACE module mechanical specifications (PDF file) are missing very essential measures, like the positions of the connectors and some others.

Answer: Please be more specific

Sure, in the top view the following dimensions are missing:

Position of the two 100-pos connectors. Preferably given by the position of the drilling holes.
Position of all 3 mounting holes.
The cutouts on all 4 corners are missing their height and width and (only the ones at the top) the curve radius.
The dimension arrow head on the upper left side doesn't end at the top of the board but at the top of the equippable space. So adding the vertical dimensions together will get you 49.35mm instead of the correct 49.85mm.

The bottom view has similar problems but it might be a bit difficult to dimension it.
Actually, the PDF is not intended to be used for dimension reference. The DXF file contains all dimension information.
sonnenfl wrote:I've drawn circles to show the 5mm on both sides that could in theory be used by a FACE module.
Is there some reason why the official documentation specifies the module to be smaller than possible?
The bottom of fit-PC3 is slightly curved and does not allow the FACE module PCB to be wider than it currently is.
sonnenfl wrote:On page 15 of the "FACE module design guide" I found the following text:
"SLP_S3# signal may be utilized to implement power supply control. Please note SLP_S3# polarity requirements."
What are these polarity requirements? I couldn't find them in the document.
The SLP_S3# signal is active low. Please see the detailed signal description in table 11 on p.11 of the "FACE module design guide" document.
Additionally, please note that in the first batch of Intense PC the polarity of this signal is reversed in respect to the documentation (and to fit-PC3). This has been already fixed and future batches of Intense PC will have this signal working as stated in the "FACE module design guide" document.

sonnenfl
Posts: 10
Joined: Thu Oct 11, 2012 11:48 am

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by sonnenfl »

igor wrote: Unfortunately there are no pins that were specifically dedicated for that purpose. I'll ask engineering to check if any pins can be used for that and update you if they find anything suitable.
Thanks.
igor wrote: Actually, the PDF is not intended to be used for dimension reference. The DXF file contains all dimension information.
Ok, I eventually did it that way too. Then what is the purpose of the PDF? ;)
igor wrote: The bottom of fit-PC3 is slightly curved and does not allow the FACE module PCB to be wider than it currently is.
OK, thanks.
igor wrote: The SLP_S3# signal is active low. Please see the detailed signal description in table 11 on p.11 of the "FACE module design guide" document.
Additionally, please note that in the first batch of Intense PC the polarity of this signal is reversed in respect to the documentation (and to fit-PC3). This has been already fixed and future batches of Intense PC will have this signal working as stated in the "FACE module design guide" document.
Good to know that.


So what is happening with the LVDS signals documentation? I haven't gotten an answer on that question yet:
sonnenfl wrote: LVDS signals missing in FACE module design guide
As seen here LVDS signals from the graphics chipset are available to FACE modules.
The FACE module design guide doesn't mention LVDS at all.
I found some infos in the FACE module design package (in the schematic of the LAN FACE module).
Can someone please update the design guide to include information about the LVDS pins?
For example:
What does LVDS_VDD_EN do?
What do the LVDS_BKLT_* signals do?
There are the pairs LVDS_CTRL_[CLK,DATA] and LVDS_I2C_[CLK,DATA]. Which one ist the DDC channel? And what is the other one?

I'm a bit in a hurry and need to get answers to these questions soon please.

Oh, and I've found a small error in the FACE module design guide:
On Page 13 the signal name of Pin B3 is certainly not PCIE_P2_TX_N because that's already used in the PX1 connector and having only one half of a differential pair is pretty useless.

-- Florian

gabrielh
Site Admin
Posts: 1260
Joined: Thu Jun 02, 2011 1:13 pm

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by gabrielh »

What does LVDS_VDD_EN do?

LVDS_VDD_EN: supply enable for lcd or enable for lcd controller for example.


What do the LVDS_BKLT_* signals do?

turn on\off back-light for lvds panel

LVDS_CTRL_[CLK,DATA]

use for configuration of work mode if display panel need that.

LVDS_I2C_[CLK,DATA]. is the DDC channel
Gabriel Heifets

Fit-PC2/3/IntensePC support.

sonnenfl
Posts: 10
Joined: Thu Oct 11, 2012 11:48 am

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by sonnenfl »

Thank you.

-- Florian

sonnenfl
Posts: 10
Joined: Thu Oct 11, 2012 11:48 am

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by sonnenfl »

Actually I got another question:
Is there some pin that I can use to signal the GPU if a display is connected to the LVDS lines?
Something like the "Hotplug" pin on DVI and HDMI connectors.

And another one:
What is the level of the DDC lines (LVDS_I2C_CLK and LVDS_I2C_DATA).
Is it 5V like in DVI/HDMI cables or is it 3.3V or somerhing else?
I couldn't measure anything. Do I have to add pull-up resistors myself?

-- Florian

gabrielh
Site Admin
Posts: 1260
Joined: Thu Jun 02, 2011 1:13 pm

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by gabrielh »

You don't have a standard hot plug detect signal in lvds interface but you can use any GPIO for this purpose (you will need take care for compatibility logic on the display ).

LVDS_I2C_CLK and LVDS_I2C_DATA - we have pull-up to 3.3v (3V3_SO on the fit-pc3).

Please pay attention we haven't lvds out on the fitpc3 FACE module external connectors.
Gabriel Heifets

Fit-PC2/3/IntensePC support.

sonnenfl
Posts: 10
Joined: Thu Oct 11, 2012 11:48 am

Re: FACE module hardware design questions (LVDS, eDP and oth

Post by sonnenfl »

EDIT: Before you answer this, please first read my next post (on page 2) as the problems below no longer exist.
gabrielh wrote:You don't have a standard hot plug detect signal in lvds interface but you can use any GPIO for this purpose (you will need take care for compatibility logic on the display ).
Well, the problem I have at the moment is, how to tell the GPU that there is a display available on the LVDS lines.
The only display that I can select in the Windows display dialog window is the one I plugged into the HDMI port.
The Intel configuration tool also only has this external display listed.
It's like the GPU has no idea that it has an LVDS output available.

I haven't done very much in the embedded graphic area in the past so I searched a bit and found a program by Intel called "Binary Modification Program" (BMP) which can change the VBIOS configuration.
Is this program needed to activiate the LVDS output and (like you said above) use an GPIO pin for display detection?
Alternatively, can CompuLab provide a VBIOS update that enables the LVDS port for those users that need it?

I've also found an Intel document that states that the "GMBUS port 2 (LVDS)" is used to detect LVDS displays at boot.
Is this port available on the FACE module connectors?
Here is the document: http://www.x.org/docs/intel/HD/IHD_OS_V ... t4_BJS.pdf (Page 109, in the "LVDS_detected" box)
gabrielh wrote: LVDS_I2C_CLK and LVDS_I2C_DATA - we have pull-up to 3.3v (3V3_SO on the fit-pc3).
I'm sorry, but I can't measure any DC voltage on those two pins at all.
I've also tested with an 350MHz scope with 4 GSamples/sec and triggered on positive or negative edges.
Nothing. Not in booting stage, not in Windows 7 display configuration dialog and also not when I use the Intel graphics tool.


By the way, I have an Intense PC Pro Barebone with Intel i7 3517UE (1.7 GHz) and Intel HD4000 graphics, if that makes any difference.

-- Florian
Last edited by sonnenfl on Wed Oct 31, 2012 9:20 pm, edited 1 time in total.

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