Path: utzoo!attcan!uunet!mcvax!unido!tub!tmpmbx!netmbx!hase
From: hase@netmbx.UUCP (Hartmut Semken)
Newsgroups: comp.sys.atari.st
Subject: Re: RGB to composite video
Message-ID: <1907@netmbx.UUCP>
Date: 12 Jun 88 17:19:49 GMT
References: <55.229FB0C4@rubbs1.UUCP>
Reply-To: hase@netmbx.UUCP (Hartmut Semken)
Organization: netmbx Public Access Unix, Berlin
Lines: 24

In article <55.229FB0C4@rubbs1.UUCP> Robert_Lisowski@rubbs1.UUCP (Robert
Lisowski) writes: >The Motorola MC1377 RGB to PAL/NTSC converter chip is
the basis for alot of the converters out there.  The only problem is
creating composite sync (needed by this chip) from the ST's seperate
sync.  The national semiconductor MM5321N (rather expensive at
 $11.95, versus under $3.  for the motorola) is a TV camera sync
generator that outputs equalized pulse composite sync that can drive the
motorola.  The sync can be pulled off seperately from the ST and input
to the national chip's reset pins.  The nationa l >

Hmm, do you really need it? My german ST (520 ST+/1985) has a "circurit"
to do the trick: one transistor, a diode and a couple of resistors (I
never worked out, how it works :-).

But you don't need that either: just apply HSync to the composite sync
of the MC1377 and green and VSync to the green pin.
If that does not work, swap HSync and VSync. It works...

Hope to save you some money...
hase

-- 
Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP
High on a rocky promontory sat an Electric Monk on a bored horse. (D. Adams)