User avatar
michele.x
Posts: 72
Joined: Sat Sep 22, 2012 8:15 pm

Almost like CGA

Thu Nov 01, 2012 10:02 pm

This is a really silly trick you can do with the Pi connected to an analog monitor.

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It looks almost like an old CGA monitor, and reduces flicker too. That old monitor uses a tube developer for black and white tv sets so the white phosphor is fast-decay. Using this trick the flicker is a lot less noticeable.

file cga.sh

Code: Select all

#!/bin/bash
setfont Uni1-VGA8
#PAL
fbset -a -xres 640 -yres 240
#NTSC
#fbset -a -xres 640 -yres 200
reset

file vga.sh (to get back the normal font)

Code: Select all

#!/bin/bash
setfont Uni1-VGA16
#VGA
fbset -a -xres 640 -yres 480
#M24
#fbset -a -xres 640 -yres 400
reset

remember to make executable the scripts with:

Code: Select all

chmod a+x cga.sh
chmod a+x vga.sh
my config.txt has this snippet to have a 640x480 pixel unscaled framebuffer:

Code: Select all

overscan_left=16
overscan_right=0
overscan_top=16
overscan_bottom=16

sdtv_aspect=1
sdtv_mode=2


Note that if X is launched after changing the framebuffer, the vertical resolution is reduced to half.

User avatar
guidol
Posts: 65
Joined: Tue Jul 03, 2012 9:21 am
Location: Babenhausen, Germany

Re: Almost like CGA

Mon Jan 14, 2013 3:00 pm

Today I did try your config with a very small black/white TV on my RPi.
Looks very funny :-)
http://lehwalder.wordpress.com/2013/01/ ... ini-sw-tv/
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