Re: Help needed with IIc

[david@uow.edu.au (David Wilson)]

"Jedi Master" <jedimaster@no.email.com> writes:
>The monitor I picked up also has the same DB15 connector on it. It's a Model
>M0401. It appears to be a 13" or 14" monitor. One of my son's friends says
>he has the DB15 male-to-male cable and will bring it over next week. I'll
>give it a try then. It's hard to find info on the IIc, so I'm not sure about
>an adapter. Wouldn't that be needed  for a monitor with separate RGB inputs?
>JM

The 15 pin connector on the rear of a //c does not have raw RGB signals
(no Apple // other than the //gs does). It does have enough signals to allow
PAL composite or RGB separate to be generated externally. DO NOT plug
a Mac monitor directly into this socket!

Apple have used the 15pin connector for many incompatible video uses
(//c vs //gs vs Macintosh).

Here is what the comp.sys.apple2 FAQ has to say about this port:
------------------------------------------------------------------------------
~From: David Empson

022- A friend with Apple //c's and IIc+'s wants to connect them to RGB
     monitors. What is the //c/IIc+ video port pin configuration?

     First, I should correct a misconception: the video port on the back of the 
IIc+ is _not_ an RGB port.  It is a video expansion port, which provides all of 
the internal video generation signals used by the IIc/IIc+ which can be used to 
generate an alternative video output signal.

The actual functions of the IIc video port are as follows:

1   TEXT     Indicates text mode is active (spcl fn in DHR mode)
2   14M      14 MHz clock sigal
3   SYNC     Horizontal and vertical sync
4   SEGB     Vertical counter signal from IOU, or lo-res indication
5   1VSOUND  Sound output (one volt peak-to-peak)
6   LDPS     Video shift load enable
7   WNDW     Active area display blanking
8   +12V     +12 volts DC
9   PRAS     RAM row address strobe
10  GR       Graphics mode enable
11  SEROUT   Serialized character generator output
12  NTSC     Composite NTSC video output
13  GND      Ground reference
14  VIDD7    Bit 7 of video shift latch (hires mode col shifting)
15  CREF     Colour reference timing signal

These come from the IIc Technical Reference, both first and second editions.


     You cannot connect a monitor directly to the IIc video port (with the
possible exception of the the LCD display, or an NTSC monitor). To produce
RGB output (or anything else) from this port, you need an external adapter box.

     This adapter is not simple: it has to decode the colour information
from the NTSC video signal (or generate it by detecting the graphics mode
and monitoring bit patterns), generate appropriate sync signals, etc.

     I believe there is (or was) an RGB output adapter for the IIc, which should
 also work on the IIc+.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia