VGA "Not Supported Mode" on a Samsung TV
Genetix
Posts: 1,754
I used my Demo Board on my Samsung TV and only the VGA Text Demo worked.
All the other VGA demos gave me a Not Supported Mode message.
The manual for my TV lists the supported resolutions along with the Horizontal (H), Vertical (V) , and Pixel Clock (P) Frequencies.
I know that Pixel Clock is commonly talked about but how are the Horizontal and Vertical frequencies related.
For example, these are IBM supported:
640x480 H: 31.469 kHz V: 59.940 Hz P: 25.175 MHz
720x400 H: 31.469 kHz V: 70.087 Hz P: 28.322 MHz
I know that I should probably be using a real VGA monitor but information like this may help others get their displays to work or help the coders make other resolutions possible.
The rest of the table is for VEAS (whatever that is) and I will double check that I have the correct manual for my TV.
All the other VGA demos gave me a Not Supported Mode message.
The manual for my TV lists the supported resolutions along with the Horizontal (H), Vertical (V) , and Pixel Clock (P) Frequencies.
I know that Pixel Clock is commonly talked about but how are the Horizontal and Vertical frequencies related.
For example, these are IBM supported:
640x480 H: 31.469 kHz V: 59.940 Hz P: 25.175 MHz
720x400 H: 31.469 kHz V: 70.087 Hz P: 28.322 MHz
I know that I should probably be using a real VGA monitor but information like this may help others get their displays to work or help the coders make other resolutions possible.
The rest of the table is for VEAS (whatever that is) and I will double check that I have the correct manual for my TV.
Comments
If you mean VESA, that is a series of video standards, some of which apply to the resolution adn frequencies.
I do not have the link to the VESA stuff at the moment.
What resolution were you having trouble with?
Anything else in small monitors is hit or miss. New, big monitors seem to universally support 1080p @ 60 Hz.
640x480 H: 31.469 kHz V: 59.940 Hz P: 25.175 MHz
720x400 H: 31.469 kHz V: 70.087 Hz P: 28.322 MHz
Propeller Demo
VGA Demo
Microphone to VGA
VGA 512x384 Demo
VGA HiRes Text Demo
VGA Tile Driver Demo 2
VGA Tile Driver Demo 3
Only this demo worked properly - VGA Text Demo
This is from my TV manual under the section PC Display:
Display Modes
Both screen position and size will vary depending on the type of PC monitor and its resolution.
The resolutions in the table are recommended. (All resolutions between the supported limits are supported)
Mode Resolution Horizontal Vertical Pixel Clock Sync Polarity Frequency (kHz) Frequency (Hz) Frequency (MHz) (H/V) IBM 640 x 480 31.469 59.940 25.175 - / - 720 x 400 31.469 70.087 28.322 - / + VEAS 640 x 480 37.861 72.809 31.500 - / - 640 x 480 37.500 75.000 31.500 - / - 800 x 600 37.879 60.317 40.000 + / + 800 x 600 48.077 72.188 50.000 + / + 800 x 600 46.875 75.000 49.500 + / + 1024 x 768 48.364 60.000 65.000 - / - 1024 x 768 56.476 70.069 75.000 - / - 1024 x 768 60.023 75.029 78.750 + / + 1280 x 720 45.000 60.000 74.250 + / +-> The interlace mode is not supported.-> The set might operate abnormally if a non-standard video format is selected.
-> DVI does not support PC function.
-> Separate and Composite modes are supported. SOG is not supported.
I have not had an experience with VGA in a Samsung TV, but the past two decades of flat screen video development have been very fast paces and there has been a lot of litigation over intellectual property. The end result is that even if the Propeller is supposed to work, the monitor or TV port just may refuse it in some modes for reasons unknown. I have similar issues when attempting higher resolution formats in Linux.
I have also had similar issues with HDMI. And I have one supposedly HDMI capabale monitor that will only accept VGA.
Generally, I have concluded that if you try to save money by buying ON Sale and off-branded monitors, you get more problems. View-Sonic seems to have been particuarly disappointing to me.
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You could make a Puppy Linux LiveCD and boot that in your regular computer. Then you could run through a comparison of how the Samsung VGA works with alternative VGA clocking in Linux. The Propeller is programable, so it should be able to conform to anything if the right timing is provided at the right impedances and voltage levels.
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And you might check your VGA cable for length and quality. An up-grade in cable might just make all the trouble go away.
PC monitors will work with almost any timing these days. But, TVs seem to be more picky.
How old is this TV? I've also noticed that older monitors and TVs are more picky than new ones...
Rayman, my TV (LN-S2338W) was built September 2006 in TJ, Mexico. It was given to me so I can't complain. :P I've used it as a PC monitor and only had it not work once.
I have to admit that my views are from Taiwan, not the USA marketplace.
A. Samsung is not popular in Taiwan due to S. Korea being a major competitor, but S. Korea certainly supplies the USA market.
B. My bad experiences with Samsung and Viewsonic may be due to Asian electronics producers selling off their less successful products in Taiwan... stuff that may never have reached the USA market.
C. Sony? They produce nice stuff, but in Taiwan it is generally over priced.
Like Rayman said, monitors work with anything, TV's are still very picky. But I still threw out all my tube monitors anyway, they are just too bulky and use too much juice.
Maybe the thing to do is change the timing in the code for the other demos?
Yes indeed, but it seems we need a tutorial for new users to explore this with whatever they might have. Everyone has a different situation, so it is hard to sort out what exactly might work without trial and error with the actual unit.
The one other thing I do wonder about is how well the resistor network on the Propeller for VGA targets the ideal impedance. A few years back there was a thread that discussed the the values of the resistors could be altered to get a better fit. So TVs and VGA may just ignore the Propeller in higher resolutions due to the impedance matching being marginal. It is easy enough to correct, and the colors are better as well.
The other demos all look great but I did notice the VGA_Tile_Driver_Demo2 which should be 60 Hz actually was 56 Hz.
I initially thought the VGA_512x384_Bitmap_Demo didn't work because of all the horizontal line segments but after seeing Microphone_to_VGA which uses the same driver works fine and looking at the code those lines are supposed to be there.
I still need to try the Application Notes GUI code but I love the Propeller's VGA capability.