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Wrong VGA resolution Bad horizontal alignment

PostPosted: Sep Thu 29, 2011 6:39 am
by GHerzog
I have loaded the PTterminal 0.905 on a Parallax Protoboard and it functions properly.

But i have an 'auto-synch' VGA that seems to think the output is 640x480 at Hz.

The results are that I have about 10 columns of the left portion that are off the screen. I cannot make the monitor adjust to center and I cannot make the monitor recognize 1024x768, Any suggestions would be appreciated. I do realize I am not a legitimate customer at this point.

640x480 resolution is just fine if that is what is intended. But I do need to see the whole page. Right now, I can't see the cursor in the Home position and the 'Baud Rat' portion of the banner at the bottom is hidden.

Could it be something simple?

Re: Wrong VGA resolution Bad horizontal alignment

PostPosted: Sep Fri 30, 2011 1:51 am
by GHerzog
I am now going on the assumption that the 640x480 resolution @69.3Hz is intended and the misalignment can be somehow tweaked. Please advise.

Yesterday, I spent a few evening hours trying to get the firmware to realign. I attempted to manipulate ''split screen" parameters in the firmware and the location of "home". I also shifted the columns and rows up to higher resolution. In all cases, the monitor failed to recognize the VGA output. So I am back to the standard settings with the misalignment.

Next step is to look into a lower level way of adjusting this in Chip Gracey's driver.

I will try the standard configuration on another monitor to see if this is a specific monitor problem as I have purchased a replacement VGA for this old one. But I have planned to dedicate the old one to dumb terminal service and still need to make it work.

Re: Wrong VGA resolution Bad horizontal alignment

PostPosted: Oct Sat 01, 2011 11:05 am
by GHerzog
I have managed to reset the parameters in the VGA_HiRes_Text.spin file and get my VGA monitor to properly center.

While I could have possibly tweaked the 69.3HZ set up, I revised the whole scheme to a 59.4HZ 640X480 by changing the pixel clock to 25Mhz and using data for 60HZ 640x480 VGA that is freely published on the web.

I really need a dumb terminal for several projects and will adapt it to provide RS-232 and RS-485 interface.

Thanks for a great piece of software.