Dreamcast VGA Question

[junkeR]

Hello Everyone,

I have my Dreamcast hooked up to my 37-inch LCD via VGA. The resolution it outputs is 720x480 - where I had assumed the Dreamcast was only capable of 640x480? I am using a third-party Naki vga box on my launch (9/9/99) NTSC US model Dreamcast.

Here is an image of my VGA adapter:


Is this normal??

[Specineff]

Yes, it's normal. It doesn't matter what VGA box you use. You won't get any weird screen ratio unless your TV is sucky.

[PC Engine Fan X!]

Ah yes, I've got one of those Naki produced DC VGA Adapters myself which outputs at 640 x 480 spec. Perhaps your LCD TV monitor is a bit off on the output rate spec. They work like a charm just like the official Sega DC VGA adapter does. ^_~

PC Engine Fan X! ^_~

[neorichieb1971]

Its only the horizontal field thats changed. Sounds like its forced 16:9 giving that resolution. 640x480 is 4:3.

[ED-057]

DC uses a 13.4MHz pixel clock to generate a 640-pixel-wide display on a TV. With VGA output, the pixel clock is doubled to 26.8MHz, BUT... VGA monitors have a quicker horizontal retrace. The normal clock for 640x480x60hz on a VGA monitor is 25.175MHz. So the DC's display will be a little squished horizontally on a VGA monitor, and the monitor may misinterpret it as 720x480.

[szycag]

Awesome bit of info. My HDTV also makes the same mistake when bringing up the signal. Thanks ED-057