View Full Version : Drive an RGB Analog monitor
05-05-2008, 06:32 AM
Has anyone tried to drive an RGB Analog monitor with the Propeller? These monitors were common in the mid-80's and could do 640 x 200 (Non-interlaced) or 640 x 400 (Interlaced). These monitors were typically connected to Atari ST and Amiga computers. I have a nice Sony 20 inch XBR RGB Analog monitor and think it would make a good match with a Propeller displaying 80 column ASCII art http://forums.parallax.com/showthread.php?p=724964
05-05-2008, 08:46 AM
I have been using the VGA driver with a slight modification to drive an Analog RGB LCD unit. You can send HSYNC and VSYNC into an XOR gate to obtain a composite sync signal, or you can modify the driver to do the XOR in software. Just change the line that toggles the VSYNC to toggle the HSYNC instead and the HSYNC pin becomes a composite sync.
Can you post your composite driver to object exchange, or attach it here for the PASM impared?
I think with such a monitor you could just use the VGA drivers. They should support normal VGA syncs. If they do not well using an interlaced mode with half the hsync will solve the problem. I unassembled a 20" Sony Trinitron monitor (SGI branded) it could do 800x600 @ 120 Hz or maybe it was only 640x480... very nice. That was quality! Are you sure yours cannot ?
Actually, mine is a 5.5" Sony PSone LCD Yes, I am sure it cannot, but I did fine that Timmoore wrote a driver here:
If you want more information on it, check out these links:
As you can see it is a very versitile little monitor. With the proper mods, it will take VGA, Composite, Svideo inputs. Very nice.
After doing a bit of experimenting and straining through a magnifying glass, I have concluded that the resolution of the PSOne LCD is actually only about 320x240, definitely not 640x480.