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peter
peter
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Hi all,

I am trying to connect the NHD 5-0 800480 TF-ATXL#-CTP (see attached) to the IGEPv2 board. I am using "out of the box" IGEPv2 with the only software change being
omapfb.mode=dvi:1024x768MR-16@60
changed to
omapfb.mode=dvi:800x480MR-24@60 since the NHD has a 800x480 resolution.

My connector board is very simple - taking the lines from igepv2 JA41 and JA42 pins (1.8volts) translating them all with TXS0108E chips, and feeding to the NHD display - see attached.

The backlight works - I have an external power supply. The screen doesn't. I am getting a darkened screen and a few red green blue lines when I power up the IGEPv2 connected to the NHD 5-0 800480 TF-ATXL#-CTP. HDMI does work fine.

My questions are
1. Does IGEPv2 supply a video DEN (data enable) signal? If not, should I tie DEN high? I tied ACbias signal to DEN which I think is wrong.
2. IGEPv2 clock signal JA42 is a sine wave on the oscilloscope. After translation via TXS0108E it is a very strange wave? Should the clock signal be translated?




I checked the lines with an oscilloscope.
BEFORE TRANSLATION VIA TXS0108E I GET THE FOLLOWING....

rgb data 24 bits = spike 1 volts @ 30 microseconds interval
Vsync = spike 2 volts @ 18 milliseconds interval
Hsync = spike 2 volts @ 25 microseconds interval
(grouped in 2 second intervals - half second on and 1.5 seconds off )
Acbias (tied to DEN)= spike 2 volts @ 32 microseconds
PUP = not measured and not connected
PCLK = SINE WAVE -1 volt to +2.5 volts at 10 millisecond wavelength
+? another sine wave same amplitude @ 25 nanosecond wavelength


AFTER TRANSLATION VIA TXS0108E FOR ALL SIGNALS I GET THE FOLLOWING....
rgb data 24 bits = spike 3.3 volts @ somewhat messy on for 7ms off for 7ms
= but on/off randomly every 5 microseconds
Vsync = spike 3.3 volts @ 18 milliseconds interval
Hsync = spike 3.3 volts @ 25 microseconds interval
(grouped in 2 second intervals - half second on and 1.5 seconds off )
Acbias (tied to DEN)= spike from 3.3volts to 0 volts @ 32 microseconds
= 3.3v for 29 microseconds and 0 v for 3 microseconds
PUP = not measured and not connected
PCLK = extremely messy - VERY thick wave 10ms wavelength
+ funny sine wave at 25 nsec wavelength
Responses (3)
  • Accepted Answer

    Tuesday, October 20 2015, 01:18 PM - #permalink
    0
    Hi Peter,

    I answer below

    I am using "out of the box" IGEPv2 with the only software change being
    omapfb.mode=dvi:1024x768MR-16@60
    changed to
    omapfb.mode=dvi:800x480MR-24@60 since the NHD has a 800x480 resolution.

    It is not a proper way to configure and LCD panel without standard HDMI resolutions. In your case a better way will be create a new display data platform, look lcd-70 (seiko) and lcd-43 (powertip) from:
    http://git.isee.biz/?p=pub/scm/linux-omap-2.6.git;a=blob;f=arch/arm/mach-omap2/board-igep00x0.c;hb=c9aac4fd20f833099f658a654257f2295c5303bb
    http://git.isee.biz/?p=pub/scm/linux-omap-2.6.git;a=blob;f=drivers/video/omap2/displays/panel-powertip-ph480272t.c;hb=c9aac4fd20f833099f658a654257f2295c5303bb
    http://git.isee.biz/?p=pub/scm/linux-omap-2.6.git;a=blob;f=drivers/video/omap2/displays/panel-seiko-70wvw1tz3.c;hb=c9aac4fd20f833099f658a654257f2295c5303bb

    The backlight works - I have an external power supply. The screen doesn't. I am getting a darkened screen and a few red green blue lines when I power up the IGEPv2 connected to the NHD 5-0 800480 TF-ATXL#-CTP. HDMI does work fine.
    What is your HDMI output resolution?

    Does IGEPv2 supply a video DEN (data enable) signal? If not, should I tie DEN high? I tied ACbias signal to DEN which I think is wrong.
    I think that DVI_ACBIAS is DEN equivalent signal

    IGEPv2 clock signal JA42 is a sine wave on the oscilloscope. After translation via TXS0108E it is a very strange wave? Should the clock signal be translated?
    It will be easier to understand if you post some captures.

    Cheers!
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  • Accepted Answer

    peter
    peter
    Offline
    Wednesday, October 21 2015, 04:13 AM - #permalink
    0
    Thanks so much for the reply. It was excellent!

    Attached are oscilloscope pictures of the signals - direct from JA41 + after passing through TXS0108E on my connnector board. I am suspicious of the clock signal - is it supposed to be a sine wave?

    I will work on a driver for the NHD 5-0 800480 TF-ATXL#-CTP as suggested. I was suspicious that I might need a driver. Thanks for the pointers to similar drivers I can use.

    It is a Samsung screen that I have working with the HDMI, not the NHD 5-0 800480 TF-ATXL#-CTP.

    I sounds like my connector board design is ok?

    Peter
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  • Accepted Answer

    Thursday, October 22 2015, 10:38 AM - #permalink
    0
    Hi peter,

    I answer bellow:

    Attached are oscilloscope pictures of the signals - direct from JA41 + after passing through TXS0108E on my connector board. I am suspicious of the clock signal - is it supposed to be a sine wave?

    I cannot see any attached file. What is your sine wave PCLK frequency?

    I will work on a driver for the NHD 5-0 800480 TF-ATXL#-CTP as suggested. I was suspicious that I might need a driver. Thanks for the pointers to similar drivers I can use.

    Seiko 70wvw1tz3Z3 driver is a good starting point for your display controller

    I sounds like my connector board design is ok?

    I think so, but I suggest you to use unidirectional level translators for your video lines, these IC tends to be cheaper and faster. IGEP BERLIN uses SN74AVC16T245

    Cheers!
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