[Coco] I2C - Is it possible?

[T. Franklin]

Ooops, I never considered the hardware aspects in my response. I just figured that a small hardware device using simple addressing and an I/O ports with associated hardware would be used. It's still possible with said hardware implementation.

-----Original Message-----
From: gene heskett [mailto:gheskett at wdtv.com]
Sent: Saturday, July 23, 2011 10:31 AM
To: coco at maltedmedia.com
Subject: Re: [Coco] I2C - Is it possible?

On Saturday, July 23, 2011 11:11:42 AM James Dessart did opine:> On Sat, Jul 23, 2011 at 4:42 AM, Nick Marentes  wrote:> > Just wondering if anyone has any idea if it's possible to 'bitbang' an> > I2C interface on the CoCo?> > > > There so many tiny I2C circuits available (including VGA) that I was> > wondering if there was any way to bring some of these devices to the> > CoCo?> > Wikipedia has this to say:> http://en.wikipedia.org/wiki/I�C#Example_of_bit-banging_the_I2C_Master_p> rotocolFrom what I get from this article, the coco's bit banger port is not capable since both lines need to be both bidirectional and open collector for output. I would think a suitable chip could be cobbled up and made to work under nitros9, possibly even somewhat along the lines of The Forgotten Chip idea but with a separated jack. I built that, and used it in a coco2 for about 14 years in my EDISK kit for the tv station. Zero problems with it.We had one device there at WDTV that used I2C. When they said that protocol was distance limited to 39 feet, they meant it. The control head for an effects device needed to be beside the switcher's panel so that the CG operator immediately to the TD's right could reach it. The unit also needed to be within a 2 foot range of the switchers main rack for color phasing matching. This resulted in a trench run of about 42 feet. Could not be made to work. I finally ran the control cable straight up into the suspended ceiling and ran it across the tiles to a point above the control position & dropped down to it, which allowed me to cut about 3.5 feet off the cable. At 38.5 feet, it worked flawlessly. But that experience pretty well dynamited any chances of us buying any more gear that used I2C for a control interface.Cheers, gene-- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order."-Ed Howdershelt (Author)We come to bury DOS, not to praise it.(Paul Vojta, vojta at math.berkeley.edu, paraphrasing a quote of Shakespeare)--Coco mailing listCoco at maltedmedia.comhttp://five.pairlist.net/mailman/listinfo/coco