Charlie wrote:
On 10/6/2011 5:13 PM, IUnknown wrote:On Oct 6, 12:38 pm, Antoine Vignau<antoine.vig...@laposte.net> wrote:Dear All, Every week pops up the same question about modern video displays for our Apple IIs. Will we get a definitive answer to that concern? AntoineIn a nutshell, there are two solution(s). 1 - Find a compatible monitor. 2 - Purchase a device that bridges that electrical gap between the IIgs and modern monitors/displays. Both approaches have significant negatives associated with them. Until a hardware device is available that will perform a 'true' conversion of the IIgs video signal to VGA, we are pretty much stuck.A hardware device doesn't have to 'convert' the IIgs video signal to VGA. It can generate the VGA directly from the video data in the Apple memory. This is the way the Second Sight card works (I believe) as well as the Carte Blanche card. However, solution 1 (finding a compatible monitor) is probably still the easiest and cheapest and overall gives adequate results.
The problem is that any device that proposes to generate VGA video from an Apple II (of any stripe) must also faithfully (instantaneously) render the results of rapid video mode switching--a very difficult feat for non-native video generation. Converting the video output is by far the most compatible approach, and it's not difficult--it's just that none of the currently available devices was designed to convert video generated by an Apple II (or an Apple IIgs, for which SHR is a special problem because of its 16MHz dot clock). Any device that samples the video at the dot clock frequency will do a perfect job of converting Apple video to *analog* VGA. If you want to use a *digital* VGA monitor (like an LCD), then you also have to generate VGA video with a proper *VGA* dot clock--making for an interesting (difficult) resampling problem. This, by the way, is the same problem that occurs when Apple II video is applied to an LCD that supports NTSC scan standards. -michael NadaNet 3.1 for Apple II parallel computing! Home page: http://home.comcast.net/~mjmahon/ "The wastebasket is our most important design tool--and it's seriously underused."