[Coco] [Color Computer] Re: POKE 65495,0

[jdaggett at gate.net]

On 5 Feb 2007 at 19:25, James Diffendaffer wrote:


> --- In ColorComputer at yahoogroups.com, "James Diffendaffer"

> <jdiffendaffer at ...> wrote:

> >

> > 

> > >> Could it even be that different production runs of the SAM have

> > >> different behaviors?

> > >>

> > >> JCE

> > >>

> > >

> > >There was a second generation of the SAM chip called 74LS785 that I

> > > think appeared in the Coco2. One of its main features was to

> > >extend the refresh counter from 7 bits to 8 bits. This allowed the

> > >usage of 64Kx1 dram chips. Since I don't have a spec sheet on the

> > >74LS785, so I can't verify that any other functions have changed.

> > >From what I have read the 74LS785 is pin for pin compatible with

> > >the 74LS783/MC6883.

> > >

> > >james 

> > 

> > Actually, I think the newer SAM included a built in latch to reduce

> > the motherboard parts count.  I don't think the pinout would change

> > much but it would function differently.

> 

> Or was it the new version of the VDG that added the latch... not sure.

> 

***********

I believe that the MC6847T1 had the latch. 

It also had lower case character as part of the character ROM. 


james