CoCo 3: is the video driver memory-mapped graphics?

CoCo 3: is the video driver memory-mapped graphics?

Post by Douglas Beattie Jr » Tue, 26 Mar 1996 04:00:00



I saw a CoCo 3 running OS-9 Level II the other day, and the hi-res
80x24 display was terribly slow.  Just out of curiousity, is there
a CRTC inside a CoCo 3, or is it some strange bit-mapped graphics
scheme that produces that 80x24 text window?

Would it be substantially faster if the fellow were using a
different display output driver (perhaps directly to a 6845)?

--
Douglas Beattie Jr.            http://www.whidbey.net/~beattidp

 
 
 

CoCo 3: is the video driver memory-mapped graphics?

Post by David M. Graha » Tue, 26 Mar 1996 04:00:00



Quote:>I saw a CoCo 3 running OS-9 Level II the other day, and the hi-res
>80x24 display was terribly slow.  Just out of curiousity, is there
>a CRTC inside a CoCo 3, or is it some strange bit-mapped graphics
>scheme that produces that 80x24 text window?

>Would it be substantially faster if the fellow were using a
>different display output driver (perhaps directly to a 6845)?

Douglas, the CoCo 3 uses a custom GIME (Graphics Interface Memory Expansion )
chip.  It is indeed bitmapped.  The slowness you noted was likely a result
of the systems stock software.  The new Nitros/OS-9 systems take advantage
of sytems module updates and a 6309 CPU replacement to FLY.  In fact, such
a system is measureably faster than some 68xxx systems, wherefor the same
programmer is now optomizing K-Windows for the MM/1.  (K-Windows is the
MM/1 Windowing system which offers CoCo OS-9 Level II Windowing compatibility.

and more).

David
--
-------------------------------------------------------------------------------
|   David M. Graham      |          President of BlackHawk Enterprises, Inc   |

|                        |          Running  OS9/68000 on a 68070 CPU         |
|=============================================================================|
|   Anything running a Motorola Processor is better than an IBM clone!        |
|=============================================================================|

 
 
 

CoCo 3: is the video driver memory-mapped graphics?

Post by Bob Palm » Sat, 30 Mar 1996 04:00:00



Quote:

>I saw a CoCo 3 running OS-9 Level II the other day, and the hi-res
>80x24 display was terribly slow.  Just out of curiousity, is there
>a CRTC inside a CoCo 3, or is it some strange bit-mapped graphics
>scheme that produces that 80x24 text window?

I don't really know what would make it faster but the COC III has a special
purpose chip which Tandy labeled the "Advanced Color Video Chip".
 If you have a schematic that's IC6.  That chip runs all the video plus
provides the memory management.  All in all rather closely bound
to the machine.  Actuallg I never thought of it as particularly slow.
Remember that were talking 1.9 MHz clock rate.

The text does not requre you to pay with bit mapping, even on a
 graphics window.

Bob

 
 
 

CoCo 3: is the video driver memory-mapped graphics?

Post by DSRT.. » Sun, 31 Mar 1996 04:00:00


Quoting "DouglasBeattieJr."<beattidp from a message in comp.os.os9
   >I saw a CoCo 3 running OS-9 Level II the other day, and the hi-res
   >80x24 display was terribly slow.  Just out of curiousity, is there
   >a CRTC inside a CoCo 3, or is it some strange bit-mapped graphics
   >scheme that produces that 80x24 text window?
   >Would it be substantially faster if the fellow were using a
   >different display output driver (perhaps directly to a 6845)?
   >--
   >Douglas Beattie Jr.            http://www.whidbey.net/~beattidp
   >.

There is a screen speed-up utility from Chris Dekker in Canada that boost
speed a great deal. I believe there is both a 6809 and 6309 version of the
re-written screen drivers.

Francis (Frank) G. Swygert
Editor/Publisher, "the world of 68' micros" Magazine                                                              

 
 
 

1. Memory-mapped device driver

I would like to write an OS/2 device driver to access memory in an image
processing board which was 1 MB of onboard memory. The board can be
set up to be mapped into a 64K window under 1Mb mark, or to a 1MB linear
space above 1Mb mark. I would like to use the later mode of operation.

I was reading the "Writing OS/2 Device drivers in C" in which this two
froms of memory mapping are mentioned. The example provided only shows the
set up a for the 64K window though. I thought of modifing the driver
to use a larger space but the PhystoUVirt function only takes a USHORT
as a size parameter. I presume this is not the currect appoach.

Any suggenstions will be appeciated.

Regards,
Jaime

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