John-Robert La Porta ha escrito: > As much as this subject has been beaten over the head, I have seen > lately a lot of interest on the list about how to obtain video from > compacts, and others searching for analog board pin-outs. I still need > a way to get video from a Plus/SE/Classic and preserve its 512 x 342 > resolution. If anyone knows how to do this, or has any ideas of how to > get this type of picture on to a standard TV screen, any help would be > appreciated. I am working on a big project and this is all that is > holding me back. Thanks.
Simplifying it, there are basically two kinds of computer monitors: composite and high resolution. Composite monitors can only handle signals with the same specifications as TV signals (525 interlaced lines per frame at 60 Hz for NTSC), that are far bellow the compact Mac's specification (about 400 non-interlaced lines per frame at 60 Hz). Most high resolution displays are designed for resolutions of, at least, 640x480 (about 525 non-interlaced lines), and so they won't operate with a compact Mac's signal, because they are far above it (modern monitors and adapters do support a 512x384 mode, but do that by using pixel-doubling -drawing each pixel *four* times in a 1024x768 arrangement- to maintain it within valid values). But the EGA graphics adapter for the PC (read the whole paragraph before interpreting this as a flame) has a 640x350 resolution at 60 Hz, very close in horizontal and vertical frequencies to the compact Mac's 512x342 at 60 Hz (note that both have a vertical retrace rate of 60 Hz, and that 342 lines is only 2.3% out of the EGA's 350 lines). Furthermore, that graphic adapter used TTL output, so its monitors can be hooked directly to 74xx ICs. All this make EGA monitors (specially monochrome ones) a perfect candidate to hook up to a compact Mac. And I think they aren't very hard to find. Just take note that I'm not 100% sure about this, but it seems a very good possibility. If you want to engineer a compact-to-EGA adapter, I can provide you with the pinout and signal specifications for the EGA's monitor port. Greetings, Antonio Rodr�guez (Grijan) -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
