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Forum Index : Microcontroller and PC projects : VT 100 Ascii Video Terminal adjust image

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Vampire05
Regular Member

Joined: 06/12/2020
Location: Germany
Posts: 88
Posted: 04:48pm 20 Apr 2021
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Hello people,
is it possible to resize / shift the (VGA) video image on the ASCII Video Terminal. The first two characters are not visible:




PS: My monitor has no options to adjust the image  
 
Geoffg

Guru

Joined: 06/06/2011
Location: Australia
Posts: 3292
Posted: 10:43pm 20 Apr 2021
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  Vampire05 said  My monitor has no options to adjust the image  

That cannot be correct, at least you should have an "auto set" button or something similar.

The short answer is no, you cannot change the video timing.  

Video is generated by (mis)using the SPI interface on the PIC32 chip and that is limited in the timing that it can use - and that in turn determines the alignment on the screen.  Remember, the whole terminal is contained in a single chip costing $4, it is amazing that it can be coaxed into generating VGA video in the first place.

Geoff
Geoff Graham - http://geoffg.net
 
Vampire05
Regular Member

Joined: 06/12/2020
Location: Germany
Posts: 88
Posted: 11:06pm 20 Apr 2021
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Hi Geoffg, thank you for your answer.

My Monitor is not a really monitor, it is a cheap tv with vga input  

So, its ok. I will take an real Monitor.

By the way, i love your ascii terminal. It is my favorite development environment. Great work Geoffg
 
TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283
Posted: 11:48pm 20 Apr 2021
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A TV might have a setting for 'overscan' or 'underscan'
When used as a TV, it will be overscanning causing the edges to be lost.
Some TV's have a setting for 'PC' which is the same as 'underscan' where the image is shrunk so the edges are seen.

Jim
VK7JH
MMedit
 
frnno967
Senior Member

Joined: 02/10/2020
Location: United States
Posts: 104
Posted: 11:56pm 21 Apr 2021
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Also check if the TV has a "zoom" or "scaling" setting. Sometimes setting that to Normal or Full fixes it if you don't see an overscan setting.
Jay Crutti: Ham Radio Operator, K5JCJ. Computer Enthusiast. Musician. Engineer.
 
Vampire05
Regular Member

Joined: 06/12/2020
Location: Germany
Posts: 88
Posted: 09:05am 22 Apr 2021
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I have checked all TV Functions, no zoom, no over-/underscan. It is a very cheap TV   Now i use an old Computer Monitor. This works perfectly! Thank you for help guys.
 
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