[Coco] CoCo 3 68000/RAM board project

[jdaggett at gate.net]

On 8 May 2009 at 18:16, Stephen Adolph wrote:

> Power up of the machine may be delayed while the FPGA downloads it's
> brain.  Any idea what to expect?
> 
> ..Steve
> 

Just ball park figures. Using serial configuration methods either from the 
platform prom or from SPI flash should be less than a second.

power suppplies will stablize within 50 mS. After that there is a 5mS for the 
configuration to start. Here is where the major delay can occur. Since there 
will be two FPGAs if I daisy chain off of one platform flash or a large SPI 
flash then I double the configuration time since one configures then the 
other. I can also design so that both FPGAs configure at the same time 
with their own separate configuration memory. Then I have to halt 
configuration of one until the other confiures. Still in all I would expect less 
than a second before the start of code execution. 

Each FPGA should configure in less than 300mS for XC3S250E. The 
XC3S500E could add another couple hundred mS to the time.

james 



james 
> On Fri, May 8, 2009 at 5:58 PM,  <jdaggett at gate.net> wrote:
> > Frank
> >
> > My thoughts to were along that line. Most of the enhancements would
> > be best used by OS9. I still have the ability to run DECB in a
> > window and using a modern monitor. There are a couple of ways to do
> > this. WIth an SPI interface storing and retrieving programs and OS'
> > are rather easy. The XC2S250E has 12 2Kbyte block rams that can be
> > configured as ROMs. It would be no real problem to write a small
> > bios that can be used to boot DECB or NitrOS9/OS9.
> >
> > james
> >
> > On 8 May 2009 at 17:35, Frank Swygert wrote:
> >
> >> This makes the most sense James! While any software written for the
> >> enhanced machine will only run on it, running older software
> >> shouldn't be a problem. The dual processor machine would at a
> >> minimum need an enhanced version of Nitros-9 (or OS-9) just to be
> >> able to run at all -- zero backwards compatibility, even of the
> >> operating system. Even the DECB fans like myself realize that it's
> >> not conducive to easy backwards compatible enhancements, but Nitros
> >> is. And I realized a long time ago that OS-9 is where all the real
> >> activity is, especially for new stuff. Not much for DECB. If you
> >> just want DECB it's easy enough to keep an old CoCo running or use
> >> an emulator.
> >>
> >> -------
> >> Date: Fri, 08 May 2009 13:24:25 -0400
> >> From: jdaggett at gate.net
> >>
> >> All are good ideas.
> >>
> >> Considering that the GIME has limited video capabilities, enhancing
> >> the graphics ability of the GIME chip you eliminate the second 6809
> >> to do graphics This can be done by building into the new GIME a
> >> graphics processor that takes commands and draws the polygon and
> >> line shapes within the configurable graphics window.
> >>
> >> I lean to more enhancing the graphics capability of the GIME chip
> >> over a dual processor 6809. Unless you have OS9 modified to handle
> >> dual processors, a coprocessor makes better since with enhanced
> >> graphics. Also consider this, a FPGA based system can be made to
> >> run considerably faster than the current Coco3. About ten times
> >> faster.
> >>
> >> --
> >> Frank Swygert
> >> Publisher, "American Motors Cars"
> >> Magazine (AMC)
> >> For all AMC enthusiasts
> >> http://farna.home.att.net/AMC.html
> >> (free download available!)
> >>
> >>
> >> --
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> >
> >
> >
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