[Coco] COCO Video

[Steve Bjork]

On 6/23/2013 10:52 PM, Mike Pepe wrote:
> John, you've probably been asked this before, but what do you think of the
> theory that the 6847 and 6883 were designed specifically for Tandy? The 6883
> in particular smells like a breadboard of TTL glue that got the old
> shrinkeroo into a 40 pin DIP.
>

Truth be told, the 6847 (VDG) 6883 (SAM) chip was NOT design for Tandy.

The support chips like the SAM are standard affair in any CPU lineup.  
They simple help computer designers build a using that CPU.

If the SAM chip was design for Tandy there would not have been the 
Dragon or other CoCo like computers using the SAM.  (Tandy design chips 
like the Salt of the CoCo 2&3 and GIME of the CoCo3 were never used by 
outside companies.)

To this day, both Intel and AMD have support chips for their CPU. That 
big old chip on a motherboard helps interface the CPU to all that other 
stuff in the computer.  (Just like the SAM & GIME chip did many, many 
years ago.)

About year before the CoCo came out, the $250 Electric Crayon from 
Percom hit the market.  This was standalone computer that plug into the 
TRS-80's printer port and output a NTSC video display using a 6847 VDG 
chip.  I used a number of them to create color information displays for 
cable systems.

As you can see, I already knew how to use the 6847 before the CoCo hit 
the market.  That's one of the reason why DataSoft hired me to create 
their Color Computer department.

Steve