Tegra K1 Output Video Frequency
Hello all! I am using Tegra K1 in my project for rendering graphics and generating a video. My goal is to output VGA video of 1024 x 768 resolution at 50 Hz frequency. Tegra outputs HDMI video so i need a converter from HDMI to VGA. My question is does TegraK1 supports 50 Hz video on the specified resolution ? If yes, then what will be the settings to achieve it ? Regards, Ather
Hello all!
I am using Tegra K1 in my project for rendering graphics and generating a video. My goal is to output VGA video of 1024 x 768 resolution at 50 Hz frequency. Tegra outputs HDMI video so i need a converter from HDMI to VGA. My question is does TegraK1 supports 50 Hz video on the specified resolution ?
If yes, then what will be the settings to achieve it ?
Regards,
Ather

#1
Posted 02/08/2018 06:20 AM   
The TK1 can reach those specs...but the problem is that when using VGA instead of HDMI you are literally cutting the DDC wire...this is the wire which uses i2c to allow the video to query the monitor and ask it what its capabilities are. The data is the EDID data. The driver itself was set up to only allow settings via queried EDID. Using VGA would imply a fairly difficult task...you would need to create (or buy) an adapter which allows the EDID be programmed into that as a substitute to the monitor itself doing this. Creating the EDID to program in for a specific VGA monitor can itself be a difficult task even if all details are published for that specific monitor.
The TK1 can reach those specs...but the problem is that when using VGA instead of HDMI you are literally cutting the DDC wire...this is the wire which uses i2c to allow the video to query the monitor and ask it what its capabilities are. The data is the EDID data. The driver itself was set up to only allow settings via queried EDID.

Using VGA would imply a fairly difficult task...you would need to create (or buy) an adapter which allows the EDID be programmed into that as a substitute to the monitor itself doing this. Creating the EDID to program in for a specific VGA monitor can itself be a difficult task even if all details are published for that specific monitor.

#2
Posted 02/08/2018 08:29 PM   
Thanks linuxdev, By searching a little bit I came across Analog Device's HDMI to VGA Converter CN0282. By looking at its schematics we can see that it is providing DDC channel. Will problem still exists, that you have mentioned, if I would use this converter? Here is the link of CN0282 http://www.analog.com/en/design-center/reference-designs/hardware-reference-design/circuits-from-the-lab/cn0282.html Regards,
Thanks linuxdev,
By searching a little bit I came across Analog Device's HDMI to VGA Converter CN0282. By looking at its schematics we can see that it is providing DDC channel. Will problem still exists, that you have mentioned, if I would use this converter?
Here is the link of CN0282

http://www.analog.com/en/design-center/reference-designs/hardware-reference-design/circuits-from-the-lab/cn0282.html


Regards,

#3
Posted 02/12/2018 12:42 PM   
In theory this would work. The trick is that the EDID data is custom to every single monitor. You'd need to get the exact specs and convert to EDID format. In the old day of VGA monitors came with a driver disk. That disk wasn't actually a driver in the usual sense. The disk was a list of characteristics the monitor would accept and which the driver understood. EDID is the automatic delivery of this same information. If you can get details and wish to experiment with conversion to EDID format prior to making or purchasing actual hardware, then you could paste your test case in here and see if it shows up as expected and valid: [url]http://www.edidreader.com[/url]
Answer Accepted by Forum Admin
In theory this would work. The trick is that the EDID data is custom to every single monitor. You'd need to get the exact specs and convert to EDID format.

In the old day of VGA monitors came with a driver disk. That disk wasn't actually a driver in the usual sense. The disk was a list of characteristics the monitor would accept and which the driver understood. EDID is the automatic delivery of this same information.

If you can get details and wish to experiment with conversion to EDID format prior to making or purchasing actual hardware, then you could paste your test case in here and see if it shows up as expected and valid:
http://www.edidreader.com

#4
Posted 02/12/2018 11:37 PM   
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