Does anyone use an LCD monitor with their LC and AppleIIe card? I know the Apple Macintosh 12" RGB Display has a special video mode to support the Apple IIe resolution, which seems to not really work with my LCD screen. The LCD looks great for the regular LC desktop, but the video mode needed for the Apple IIe card looks like it isn't supported. Is there a work around? I have a 12" RGB monitor, but it doesnt' work at the moment, so I would love to figure out an LCD solution.
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Apple IIe PDS Card in an LCII with an LCD monitor
- Thread starter stevent281
- Start date
Maybe it has to do with how I'm connecting the monitor. What setup do you use?
I use a the same mac2vga adapter I use with other macs.
There are MANY different makes and models, with different numbers of switches and capabilities.
They typically can be set to a "vga" mode which will let the mac choose multiple resolutions and that is what I usually use.
They can also be set to a particular fixed resolution, which will force the mac to use only that one.
Some can be used to identify the monitor to the mac as "fixed" vs "multi" sync.
There was, as far as I can tell, no standard for the switches. I have several and the way they work is wildly different.
Using this, my iie card can't use the special mode, so it does emulation of the apple 2 resolution on a larger 640x480 screen. This is likely slower than if it could do the mode.
There are MANY different makes and models, with different numbers of switches and capabilities.
They typically can be set to a "vga" mode which will let the mac choose multiple resolutions and that is what I usually use.
They can also be set to a particular fixed resolution, which will force the mac to use only that one.
Some can be used to identify the monitor to the mac as "fixed" vs "multi" sync.
There was, as far as I can tell, no standard for the switches. I have several and the way they work is wildly different.
Using this, my iie card can't use the special mode, so it does emulation of the apple 2 resolution on a larger 640x480 screen. This is likely slower than if it could do the mode.
The Apple 12" RGB has one video mode.
The LC has two video modes that work with the Apple 12" RGB display. They have the same horizontal and vertical timing but the width of the pixels changes such that the resolution can be 512 wide (square pixels) or 560 wide (not square pixels).
For 512x384 60Hz, the pixel clock is 15.6672 MHz and the total width is 640 pixels.
For 560x384 60Hz (Apple II modes with 192 doubled lines), the pixel clock is 17.234 MHz and the total width is 704 pixels.
In both cases, the total height is 407 lines, the vertical frequency is 60.15 Hz, and the horizontal frequency is 24.48 kHz. Does your LCD support that horizontal frequency?
The Apple 12" RGB can accept both modes because it doesn't know about pixel width - it's analog, there's no pixel clock transmitted to the display so you could put a million pixels on each line and it would still work.
So, how is an LCD supposed to know the difference between a 512 wide mode and a 560 wide mode? It doesn't. First, does your LCD work with the 512 wide mode? Then it should work with the 560 mode. But it might not sample all 560 pixels? Ideally, you want an LCD with analog input that samples the pixels at 17.234 MHz or greater, regardless of the number of vertical lines. Does that exist? You would need to verify by running some test patterns - or look at the text in 80 column mode, black and white mode.
The LC has two video modes that work with the Apple 12" RGB display. They have the same horizontal and vertical timing but the width of the pixels changes such that the resolution can be 512 wide (square pixels) or 560 wide (not square pixels).
For 512x384 60Hz, the pixel clock is 15.6672 MHz and the total width is 640 pixels.
For 560x384 60Hz (Apple II modes with 192 doubled lines), the pixel clock is 17.234 MHz and the total width is 704 pixels.
In both cases, the total height is 407 lines, the vertical frequency is 60.15 Hz, and the horizontal frequency is 24.48 kHz. Does your LCD support that horizontal frequency?
The Apple 12" RGB can accept both modes because it doesn't know about pixel width - it's analog, there's no pixel clock transmitted to the display so you could put a million pixels on each line and it would still work.
So, how is an LCD supposed to know the difference between a 512 wide mode and a 560 wide mode? It doesn't. First, does your LCD work with the 512 wide mode? Then it should work with the 560 mode. But it might not sample all 560 pixels? Ideally, you want an LCD with analog input that samples the pixels at 17.234 MHz or greater, regardless of the number of vertical lines. Does that exist? You would need to verify by running some test patterns - or look at the text in 80 column mode, black and white mode.
I am using either the BMOW Syncinator or the Kero's Mac Mods VGA lite. The Monitor is a Dell 170sc. TBH I have never explicitly tried to boot it in 512 x 384 — I just know the monitor has worked. I'll see if I can force that mode.
The Syncinator per se has dip switches to sense that mode, so I'm assuming it's possible, but I can verify.
The Syncinator looks like a nice little device, wish I had one. I use an RGB adapter and a generic Chinese video converter board with my IIgs.
I think since Syncinator supports IIgs modes, it should be able to understand the IIe card's "special mode", but you may need to fiddle with it.
The VGA lite sounds like one of the mac2vga adapters I have, but with no switches. It may not be flexible enough, and just force "vga mode". This may confuse the Syncinator...or be exactly what it needs.
On the other hand, I don't know if the combo will let you do the mode. You may be stuck with a vga 640x480 mode like I do.
I think since Syncinator supports IIgs modes, it should be able to understand the IIe card's "special mode", but you may need to fiddle with it.
The VGA lite sounds like one of the mac2vga adapters I have, but with no switches. It may not be flexible enough, and just force "vga mode". This may confuse the Syncinator...or be exactly what it needs.
On the other hand, I don't know if the combo will let you do the mode. You may be stuck with a vga 640x480 mode like I do.
I'm pretty sure the Dell will only handle that resolution if the sync rates make sense to it. That may be possible with what you have.
It might be that the Syncinator will allow the "real mode" with the "real sync" which the Dell monitor can't handle. If you set everything up that way the Dell will say something like "sync rate not supported", etc.
I tried to get the "real mode" working with my Chinese board. I can't tell if it doesn't work due to the monitor not understanding (ie the Chinese board works), or the board can't handle those rates. Or both.
It might be that the Syncinator will allow the "real mode" with the "real sync" which the Dell monitor can't handle. If you set everything up that way the Dell will say something like "sync rate not supported", etc.
I tried to get the "real mode" working with my Chinese board. I can't tell if it doesn't work due to the monitor not understanding (ie the Chinese board works), or the board can't handle those rates. Or both.
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