4 Mar
2014
4 Mar
'14
3:32 p.m.
Hi all,
Does anyone have any documentation for this Data Systems 68 6847 video
board? I should have most of the parts to build it up. I'm going to get a
good, high-quality scan of the PCB, front and back, before I do that though.
http://i.imgur.com/JLJqsdx.jpg
http://i.imgur.com/vmE916Z.jpg
Looks related to the 6845 variant, but I imagine this 6847 board has more
graphical capability.
http://www.swtpc.com/mholley/DS68/VDB_Index.htm
Thanks,
Kyle
4 Mar
4 Mar
4:30 p.m.
On 03/04/2014 03:32 PM, Kyle Owen wrote:
Looks related to the 6845 variant, but I imagine this
6847 board has more
graphical capability.
For what it's worth, the 6847 is intended for use with NTSC TV sets.
Character display mode is only 32x16 making 512 characters per screen.
Characters are displayed in a 5x7 pixel format. If you use the internal
ROM, you get uppercase only. For a TV, this is fine, but is otherwise
pretty limiting.
--Chuck
6:34 p.m.
On Tue, Mar 4, 2014 at 6:30 PM, Chuck Guzis <cclist at sydex.com> wrote:
On 03/04/2014 03:32 PM, Kyle Owen wrote:
Looks related to the 6845 variant, but I imagine this 6847 board has more
So it sounds like for character display, it's basically worthless. What
about for bit-mapped displays? I'm afraid I don't know much about the
6845/6847 (I've not dealt with any sort of video generators yet), but is
the 6847 not more powerful than the 6845? I seem to see more computers
using the 6845, from best I can tell.
Thanks for the info. I imagine I'll build up this card only to rarely use
it if I'm limited to uppercase text.
Kyle
graphical capability.
For what it's worth, the 6847 is intended for use with NTSC TV sets.
Character display mode is only 32x16 making 512 characters per screen.
Characters are displayed in a 5x7 pixel format. If you use the internal
ROM, you get uppercase only. For a TV, this is fine, but is otherwise
pretty limiting.
10:38 p.m.
Well, it does have color graphcs of a sort. 64x64 4-color to 256x192
2-color.
One stopper for you may be that the output of the 6847 is 1 luminance
pin and 2 multi-level chrominance pins, pretty much tailored to drive a
MC1372 RF modulator--not RGB.
A typical system would be a 68xx series MPU, MC6883 SAM, a little DRAM,
some ROM for the MPU, and the MC1372. It's pretty much tailor-made for
a low-end TV gaming setup.
--Chuck
On 03/04/2014 06:34 PM, Kyle Owen wrote:
On Tue, Mar 4, 2014 at 6:30 PM, Chuck Guzis <cclist
at sydex.com> wrote:
On 03/04/2014 03:32 PM, Kyle Owen wrote:
Looks related to the 6845 variant, but I imagine this 6847 board has more
So it sounds like for character display, it's basically worthless. What
about for bit-mapped displays? I'm afraid I don't know much about the
6845/6847 (I've not dealt with any sort of video generators yet), but is
the 6847 not more powerful than the 6845? I seem to see more computers
using the 6845, from best I can tell.
Thanks for the info. I imagine I'll build up this card only to rarely use
it if I'm limited to uppercase text.
Kyle
graphical capability.
For what it's worth, the 6847 is intended for use with NTSC TV sets.
Character display mode is only 32x16 making 512 characters per screen.
Characters are displayed in a 5x7 pixel format. If you use the internal
ROM, you get uppercase only. For a TV, this is fine, but is otherwise
pretty limiting. 
5 Mar
5 Mar
6:48 a.m.
I built a card like this (of my own design) when I was a kid.
The MC1372 can be used as chrominance+luminance combiner without
using the RF modulator portion-- in other words, it will produce NTSC
composite video coming out which is suitable for driving various color
video monitors (although there are then some artifacts in the image
resembling wavy lines).
The MC6847 is what was in the Radio Shack Color Computer(s) both the
regular and the micro- one.
So, your graphics capability will be on par with those.
Chris
On Tuesday (03/04/2014 at 10:38PM -0800), Chuck Guzis wrote:
Well, it does have color graphcs of a sort. 64x64
4-color to
256x192 2-color.
One stopper for you may be that the output of the 6847 is 1
luminance pin and 2 multi-level chrominance pins, pretty much
tailored to drive a MC1372 RF modulator--not RGB.
A typical system would be a 68xx series MPU, MC6883 SAM, a little
DRAM, some ROM for the MPU, and the MC1372. It's pretty much
tailor-made for a low-end TV gaming setup.
--Chuck
On 03/04/2014 06:34 PM, Kyle Owen wrote:
>On Tue, Mar 4, 2014 at 6:30 PM, Chuck Guzis <cclist at sydex.com> wrote:
>
>>On 03/04/2014 03:32 PM, Kyle Owen wrote:
>>
>> Looks related to the 6845 variant, but I imagine this 6847 board has more
>>>graphical capability.
>>>
>>
>>For what it's worth, the 6847 is intended for use with NTSC TV sets.
>>Character display mode is only 32x16 making 512 characters per screen.
>>Characters are displayed in a 5x7 pixel format. If you use the internal
>>ROM, you get uppercase only. For a TV, this is fine, but is otherwise
>>pretty limiting.
>
>
>So it sounds like for character display, it's basically worthless. What
>about for bit-mapped displays? I'm afraid I don't know much about the
>6845/6847 (I've not dealt with any sort of video generators yet), but is
>the 6847 not more powerful than the 6845? I seem to see more computers
>using the 6845, from best I can tell.
>
>Thanks for the info. I imagine I'll build up this card only to rarely use
>it if I'm limited to uppercase text.
>
>Kyle
>
>
--
Chris Elmquist
7:41 a.m.
One other thing to be careful about when using the 6847 is that it was
available in both interlaced and non-interlaced versions. If you
intend to use it with an NTSC display, you'll want the 6847Y, which is
the interlaced version. If you're driving a non-interlaced monitor,
you'll want the one without the Y suffix. I learned that the hard way
about 30 years ago.
BLS
12:18 p.m.
So it sounds like for character display, it's
basically worthless. What
about for bit-mapped displays? I'm afraid I don't know much about the
6845/6847 (I've not dealt with any sort of video generators yet), but is
the 6847 not more powerful than the 6845? I seem to see more computers
using the 6845, from best I can tell.
The 6845 and 6847 are totally different devices. One is not in any sense
a superset of the other.
The 6845 is the video timing chain. That is, it dvides dow na master
clock to produce the sync signals and the signals to address the video
RAM appropriately. It does not do anythign with the data in the video
RAM. That part has to be added by the designer, using other devices.
The 6847 is mostly the video data circuit. It contains the character
genrator ROM (uper case only), dot shift register, colour encoder (to
colour differnece signals IIRC, not to NSSC or anythign liek that), and I
think a simple timing chain. The last does not have ot be used (if it
exists), it was common in 6809 systems to pair the 6847 with the 6883
SAM (Synchronous Address Multipelxer, basically a RAM controlelr and
video timing chain). I cna't rememerbr what the Acorn Atom did, that used
a 6847, but no 6883.
-tony
4:44 p.m.
On Wed, Mar 5, 2014 at 2:18 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
The 6845 and 6847 are totally different devices. One is not in any sense
a superset of the other.
Thanks for the info, Tony. I'm looking forward to building up the board and
seeing what it can do.
Kyle
12:10 p.m.
On 03/04/2014 03:32 PM, Kyle Owen wrote:
Plenty of machines have managed ot get an approximation to European PAL
video out of a 6847, I am not sure how. The European versions of the
Radio Shack CoCo, the Dragons, and the Acorn Atom being the ones that
instantly spring to mind.
-tony
Looks related to the 6845 variant, but I imagine
this 6847 board has more
graphical capability.
For what it's worth, the 6847 is intended for use with NTSC TV sets.
3944
days inactive
3946
days old
8 comments
5 participants
participants (5)
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ard＠p850ug1.demon.co.uk -
blstuart＠bellsouth.net -
cclist＠sydex.com -
chrise＠pobox.com -
kylevowen＠gmail.com