[Coco] CoCo3 RGB port question...

[Roy Justus]

Hi all
I dd use it to send operational setup data to the video
and clock chips.      The communications transfer followed
the I2C protocol with the vertical screen sync signal as
the clock and the data was channeled to the converter 
via pin 10 on the connector.  It worked but I abandoned
this method because it meant that the user had to
run the startup program blind.  Eventually I
added the Atmel Attiny microcontroler to the 
design for automatic startup.


Roy Justus
rjrtty at aol.com

 

 

-----Original Message-----
From: John W. Linville <linville at tuxdriver.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Sat, Dec 30, 2017 8:24 pm
Subject: Re: [Coco] CoCo3 RGB port question...

    At one point Roy Justus was going to use it for signaling related to tuning his VGA adapter with software running on the CoCo. I'm not sure if he ever put that to good use or not.JohnSent from my Verizon 4G LTE smartphone-------- Original message --------From: Zippster <zippster278 at gmail.com> Date: 12/30/17  7:18 PM  (GMT-05:00) To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> Subject: [Coco] CoCo3 RGB port question... Hello everyone,On the CoCo3’s RGB port, pin 10 is held high by a pull up and goes to PB3 (PIN 13) of PIA 1 (Audio).I vaguely remember a thread long ago discussing this that basically seemed to relate that this wasintended as some sort of display ‘sense’ pin, to be used to detect the presence of an RGB monitor.From what I remember it was also said that this feature was never used to anyone’s knowledge.Does anyone know if this is true, or exactly what the deal is with this pin?- Ed-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco