[Coco] MC6809 Inards

[L. Curtis Boyle]

Wasn't the GIME by VLSI? Also, there isn't anything about the hidden modes  
on Hitachi's 6309 chip, is there? I assume not, since the extra features  
were not supposed to be public knowledge.

On Wed, 04 Oct 2006 05:31:23 -0600, <jdaggett at gate.net> wrote:

> Steve
>
> I have looked for all patents since 1976 that would have been assigned  
> to Tandy
> or Radio Shack and have found nothing. That means the GIME chip had  
> nothing
> that was patentable or that the assignee is under a different company or  
> an
> individual.
>
>
> Right now I have concentrated on the MC6809 and finding all related  
> patents. It
> has been interesting reseach.
>
> james
>
>
> On 3 Oct 2006 at 20:49, Steve Ostrom wrote:
>
>> Any chance that patents could be reviewed for the hidden graphics modes
>> for the Coco3?
>>
>> -- Steve --
>>
>>
>> jdaggett at gate.net wrote:
>>
>> >All
>> >
>> >My what you can find out when you start reading patents. I was  
>> searching the US patent
>> >records for anything that might be related to the MC6809 and actually  
>> found about four or
>> >five patents that could be directly related to the processor. There is  
>> no one single patent that
>> >is, in whole, a complete description of the processor. Instead there  
>> are several patents when
>> >combined, give insight to the internal workings of the microprocessor.  
>> I even found several
>> >patents regarding the MC6820/21 PIA chip.
>> >
>> >Some interesting things that I have found:
>> >
>> >1) The MC6809 and the MC6801/3 are probably more closer related  
>> internally than the
>> >MC6809 is to the MC6800. An interesting thing is the main CPU  
>> processor core schematic
>> >for the MC6801 is included in patent # 4266270, Microprocessor having  
>> dual internal data
>> >busses. Beware this is a huge schematic if you want to print it out.  
>> It prints out to about 28
>> >letter size pages.
>> >
>> >2) It appears that there are three internal clocks in the MC6809/01/03  
>> and maybe even the
>> >MC6811/HC11.The clock system in the MC6801 patent (4266270) has three  
>> clocks. I have
>> >verified that t here are indeed three clocks running through the  
>> schematic.
>> >
>> >3) the address bus internally is split into two separate busses, A0  
>> -A7 and A8 to A15. Also
>> >As the title to patent 4266270 suggests there are two seaprate 8 bit  
>> data busses in the
>> >MC6801/3 processor. When I pulled patent 4200912 and looked at the  
>> figures #1 and #2 my
>> >eyes nearly popped out of my sockets. Here it was nearly indentical to  
>> the MC6809. Low
>> >and behold t his patent depicts a MC6809 like processor with two  
>> internal 8 bit data busses
>> >that has a switch to make the two a single 8 bit buss. The main scope  
>> of patent 4200912
>> >was a processor having multile IRQ processors. The embodied processor  
>> has the IRQ and
>> >FIRQ inputs. The registers include the USP,  Y pointer register, and  
>> the Direct Page
>> >Register. Plus a few others.
>> >
>> >I have started writing a blurb on this and hope to put it up on my  
>> webpage soon. This was
>> >neat stuff and by pouring through about ten to 15 patents,I came away  
>> with a greater
>> >understanding of what thought processes went through during the design  
>> of the MC6809.
>> >Also a greater  understanding of several of Motorola's processors and  
>> how they function
>> >internally. One t hing that I do understand better is how fast the  
>> processor can be clocked.
>> >Best I could figure is about 6 MHz and that is pushingit real hard.  
>> Three MHz is most likely
>> >the max for most parts. To many levels of logic gates to ripple  
>> through to get much faster.
>> >
>> >more later
>> >
>> >james
>> >
>> >
>> >
>> >
>> >
>>
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> http://five.pairlist.net/mailman/listinfo/coco
>>
>>
>> --
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>
>
>



-- 
L. Curtis Boyle