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July 7, 2014   Posted by: Dr. Ace Jeangle

How to program custom EDID data in HDMI converter

Use below information at your own risk. We take absolutely no responsibility for any damage accured to your PC while attempting this procedure!
EDID files for our panels are available in Support/Sources section on our website.

 
 
 
 

EDID stands for Extended Display Identification Data (EDID), and is a data structure provided by an LCD to describe its capabilities and supported resolutions to a video source (RaspberryPi, PC, Android stick, etc.) EDID is stored in EEPROM memory chip with I2C interface on LCD receiver side. In our case this is small chip U5:
HDMI-LVDS converter, EDID chip
dualLVDS EDID

We ship our HDMI converters with pre-programmed EDID data for our standard LCD panels (1280×800 for single-LVDS, and 1920×1200 for dual-LVDS converter). If you want to use it with different LCD panel and different resolution, then you should update EDID information stored in EEPROM chip. Fortunately, this is not difficult procedure, and it will not require any special hardware tools. All you need is Linux powered PC or board (like RasPi) with HDMI output and keyboard to type in terminal commands. So, run Linux, open Terminal, connect our HDMI converter to HDMI output of PC, and power it with external power supply. Others cables are not required.

  1. First of all, lets install required tools. We will need Python SMBus library to read/write data to I2C bus, and EDID decode tools to represent EDID data in human-readable form:
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    sudo apt-get install python-smbus edid-decode
  2. Then we should download edid-rw utility:
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    git clone https://github.com/bulletmark/edid-rw
  3. And write-edid script that I wrote to simplify update process:
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    git clone https://github.com/ChalkElec/write-edid
  4. Activate i2c-dev kernel module to get access to I2C bus:
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    sudo modprobe i2c-dev
  5. Now we should find which I2C bus is used by our HDMI adapter. The simplest way is to try bus numbers one by one with command like:
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    sudo ./edid-rw 0 | edid-decode
  6. In my case I found HDMI adapter on bus #3:
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    sudo ./edid-rw 3 | edid-decode

    I got output like this:

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    Extracted contents:
    header:          00 ff ff ff ff ff ff 00
    serial number:   30 e4 45 03 00 00 00 00 00 15
    version:         01 04
    basic params:    90 16 0e 78 02
    chroma info:     e8 87 96 5a 55 95 28 22 51 55
    established:     00 00 00
    standard:        01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
    descriptor 1:    4c 1d 00 ec 50 20 18 30 40 30 57 00 d9 88 00 00 00 1b
    descriptor 2:    16 12 00 80 50 20 16 30 30 20 47 00 d9 88 00 00 00 1b
    descriptor 3:    00 00 00 fe 00 43 33 47 52 4e 80 31 30 31 57 58 31 0a
    descriptor 4:    00 00 00 00 00 00 41 32 a8 00 00 00 00 01 01 0a 20 20
    extensions:      00
    checksum:        9a

    Manufacturer: LGD Model 345 Serial Number 0
    Made week 0 of 2011
    EDID version: 1.4
    Digital display
    6 bits per primary color channel
    Digital interface is not defined
    Maximum image size: 22 cm x 14 cm
    Gamma: 2.20
    Supported color formats: RGB 4:4:4
    First detailed timing is preferred timing
    Established timings supported:
    Standard timings supported:
    Detailed mode: Clock 75.000 MHz, 217 mm x 136 mm
                   1280 1344 1392 1516 hborder 0
                    800  805  812  824 vborder 0
                   +hsync -vsync
    Detailed mode: Clock 46.300 MHz, 217 mm x 136 mm
                   1280 1328 1360 1408 hborder 0
                    800  804  811  822 vborder 0
                   +hsync -vsync
    ASCII string: C3GRN€101WX1
    Manufacturer-specified data, tag 0
    Checksum: 0x9a
    EDID block does NOT conform to EDID 1.3!
        Missing name descriptor
        Missing monitor ranges

    I can recognize it by Manufacturer string that contains “LGD” – short code of LG Display company, and by resolutions numbers “1280” and “800” in Detailed mode string. For dualLVDS converter resolution will be 1920×1200

  7. Now we know I2C bus number and can program another EDID information to our HDMI adapter. But be careful to state correct bus number on the next step. Better check twice output on previous step, then check once again. If you state wrong I2C bus number, you can accidentally overwrite another I2C EEPROM with wrong data (like EDID information of main LCD panel of your notebook).
  8. We use the following command to update EDID with information from file edid_auo14.bin (in our case this is EDID information for our 14″ AUO panel):
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    sudo ./write-edid.sh 3 edid_auo14.bin
  9. Let’s check that EDID has been updated:
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    sudo ./edid-rw 3 | edid-decode

    We should have the following output for 14″ EDID data:

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    Extracted contents:
    header:          00 ff ff ff ff ff ff 00
    serial number:   06 af 3c 10 00 00 00 00 00 16
    version:         01 04
    basic params:    90 1f 11 78 02
    chroma info:     10 b5 97 58 57 92 26 1e 50 54
    established:     00 00 00
    standard:        01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
    descriptor 1:    ce 1d 56 d2 50 00 26 30 10 10 3e 00 35 ad 10 00 00 18
    descriptor 2:    df 13 56 d2 50 00 26 30 10 10 3e 00 35 ad 10 00 00 18
    descriptor 3:    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    descriptor 4:    00 00 00 02 00 0c 39 cc 0d 3c 64 0f 0c 1b 6f 20 20 20
    extensions:      00
    checksum:        0d

    Manufacturer: AUO Model 103c Serial Number 0
    Made week 0 of 2012
    EDID version: 1.4
    Digital display
    6 bits per primary color channel
    Digital interface is not defined
    Maximum image size: 31 cm x 17 cm
    Gamma: 2.20
    Supported color formats: RGB 4:4:4
    First detailed timing is preferred timing
    Established timings supported:
    Standard timings supported:
    Detailed mode: Clock 76.300 MHz, 309 mm x 173 mm
                   1366 1382 1398 1576 hborder 0
                    768  771  785  806 vborder 0
                   -hsync -vsync
    Detailed mode: Clock 50.870 MHz, 309 mm x 173 mm
                   1366 1382 1398 1576 hborder 0
                    768  771  785  806 vborder 0
                   -hsync -vsync
    Manufacturer-specified data, tag 0
    Manufacturer-specified data, tag 2
    Checksum: 0xd
    EDID block does NOT conform to EDID 1.3!
        Missing name descriptor
        Missing monitor ranges

    As you can see, Manufacturer string now contains “AUO”, and Detailed mode has resolution 1366×768, so we did everything right, and now we can use HDMI adapter with another panel (14″ AUO in our example)

 
 

2 comments posted in: blog   |   How-To
May 27, 2014   Posted by: Dr. Ace Jeangle

Urgent update on May orders

We have to delay shipment of most May orders for around 2 weeks and ask for return selected shipped orders. The reason is non-stable (counterfeit?) power switch ICs supplied by one of our Taiwan supplier. Boards passed our standard QC tests, and we already shipped around 40 orders, when got several notes from customers about non-stable work. Additional tests made in our lab showed that problem arises when board is powered for more than 3-5 minutes – power switch gets hot and unstable. As a result, LCD backlight starts flicker. Here are steps that we did regarding this problem:

  • We placed on hold shipment of ready orders. Your orders will be shipped in around 2 weeks counting from now. New ICs has been ordered and should arrive to us early next week. Then it will take several days to rework boards, make new tests, and prepare orders for shipment
  • We wrote RMA emails to customers with already shipped orders that can have this problem. If you received email with RMA request, then please read it carefully, test your board/bundle for at least 10 minutes, and let us know about results. Unstable boards must be shipped back, LCD panel/cable is not required to be returned. If you didn’t received RMA email from us, then no reason to worry – your board has power switch IC from another batch, and is not affected with this problem
  • Orders with DHL shipping option will be processed with priority
  • If your project can’t wait 2 more weeks, then please write to us email about money refund – we will issue refunds immediately after processing your email


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April 24, 2014   Posted by: Dr. Ace Jeangle

Expanding the borders

New 14" multi-touch LCD demo
  • Our new 14″ touchscreen LCD with Windows 8 – multi-touch demo:

  • First run with RaspberryPi:

New 4.3" resistive touch serial LCD
  • Assemby of our 4.3″ touchscreen LCD:

  • Demo run of 4.3″ touchscreen LCD with Arduino:

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January 16, 2014   Posted by: Dr. Ace Jeangle

Company update

Hello, everyone!

It was a long time since my last post, and I had one reason for this – big business customers came to us with large orders after they found us, and we were not ready for the big show. Big qty orders, tough deadlines and everyday online technical support. It was tough challenge for us. We tried to reserve at least some of panels from each batch to refill our online web-shop and support our community, but these panels were sold in several hours, and we again got tons of emails with requests for stock.

After couple months like this we saw only one solution – to upgrade our whole SMT production line for higher grade equipment, hire additional staff, and to automate production planning and order processing tasks. We managed to find new big office for production, sign rent, and started renovation. At the same time we ordered new SMT equipment: semi-automatic stencil printer with optical alignment, high-speed PnP from Autotronik with dual heads, new oven with nitrogen process, and PCB cleaning machines. They will arrive next Tuesday. Equipment is so big and heavy, that we have to use crane to hoist to 2nd floor, and will dismantle window to move it in. Setup and calibration will take around 1 week, after that we will have high-speed production.

Also, we work to automate our process handling and shipping procedures. Our goal is to reduce time to 1-2 hours from receiving order to shipping it to you. Yes, we are working to improve all the time.

Now, lets check out several news regarding our products:

  1. Our current 10″ LG panel (1280×800) is obsolete (got EOL status last December). We can continue to supply it only to customers who has signed supply contract with us.
  2. We have new 10″ IPS panel with resolution 1366×768, black frame, 10 fingers multi-touch with USB interface. Good news is that this panel will have integrated HDMI board like our 7″, with LVDS scaler, HDMI audio extract, and USB HID touch driver. Thus, you will be able to use it hassle-free with virtually any hardware platform. No more kernel hacks, no more resolution limitations!
  3. We also finished design of FullHD 10″ panel with capacitive touch. It will be available for order end of February.
  4. Next is small-size cheap LCD solution based on FT800 chip. Welcome, Arduino and Launchpad lovers! You will get complete 4.3″ LCD with touchscreen, audio, and SPI/I2C interface.
  5. Finally, we are starting to offer capacitive touchscreens with USB interfaces for those who has already own LCD, and just need touch interface.

Follow us on Twitter @ChalkElec to get instant updates.

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