Roger/Sarbajit-
Doug's comment that "this" is what keeps him on the FRIAM ist was
probably only partially "tongue-in-cheek".
This level of geekery is surely near and dear to half of our hearts if
the other half naturally sit and puzzle at our arcane mumblings... but
in defense of the other forms of geekery (including philosophical
maunderings), it's all good. I really appreciate the level of
engagement and interest across a broad range of topics that can be found
here.
I *do* have at least 3 of these devices (or nearly) in my collection of
"stuff", the more obvious being the digital readouts on my Sony Amp and
my Sony CD changer as well as a (longer version?) on a rack-mount USB
keyboard/trackball system designed for use with rackmount clusters.
I was expecting Sarbajit to remind me about some really obvious digital
readout that is *even* more ubiquitous that I hadn't thought of. Like
the car odometer or radio tuner... but they all seem to be of a species
of semi-special displays.. probably not custom per model or even
manufacturer, but clearly evolving and changing often. On the other
hand, their interface might very well *BE* a superset or variant of what
you describe here!
- Steve
Another mystery of these displays was solved for me the other day when
Bunnie took his Media Lab visitors to a direct chip bonding shop in
Shenzhen. On the back of the bog standard LCD display there will
often be a dome of black epoxy in place of a chip. I thought they
were hiding the chip, but in fact the dome covers a piece of raw
silicon integrated circuit glued to the board and wired to the board
with tiny wires.
-- rec --
http://learn.adafruit.com/character-lcds/overview
http://www.freaklabs.org/index.php/Blog/MIT-Media-Lab-Shenzhen-2013/MIT-Media-Lab-Shenzhen-2013-01-22-Chip-on-Board-Bare-Die-Attachment.html
freaklabs.org <http://freaklabs.org> is off-line at the moment, but
that looks like the right posting. Lady Ada's tutorial gets to the
8/4 bit bus after several pages of prelims.
Steve
Being a devotee of ancient computing devices myself, I was responding to
Doug's TRS-80 ascii comment
here's what a 16x2 LCD module looks like
http://3.bp.blogspot.com/-hN2n9HggfCw/T2TOHEMIAsI/AAAAAAAAAAc/LrJ6uy2cNrs/s1600/lcd162b-yhy.jpg
These critters are so ubiquitous that you fail to see them. These
modules have an 8 bit data bus to communicate with Z-80s, 8085 etc
(nowadays though PICS, AVRs and ATMELs). They also have a facility to
split the 8 bit data into 2 successive nibbles of 4 bits (ie 4 pins + 2
control pins= 6 pins). This allows for instance a 12 or 14 PIC (with 8 -
10 I/O lines) to be used to implement very small devices. The design
advantage ot using these standard displays versus dedicated/custom
displays is that they have no end-of-life problems. They were available
20 years ago and still seem to be going very strong with prices falling
to @ US$1 per unit
Sarbajit
On Tue, Feb 5, 2013 at 11:31 AM, Douglas Roberts <[email protected]
<mailto:[email protected]>> wrote:
You see, this is the kind of material that keeps me on FRIAM.
--Doug
On Tue, Feb 5, 2013 at 11:29 AM, Roger Critchlow <[email protected]
<mailto:[email protected]>> wrote:
The interface to the bog standard LCD display can use either 8
or 4 bits parallel, which only changes the number of outs you
need to do to fill the line buffer, which has an 8 bit byte
for each character The 8 bit character ROM often has
fascinating character sets in the high half depending on where
the surplus came from.
-- rec --
On Tue, Feb 5, 2013 at 11:16 AM, Steve Smith <[email protected]
<mailto:[email protected]>> wrote:
Sarbajit -
Can you elaborate? I think this one just flew past me...
2 lines of 16 characters with only 4 bit indexing
(alphabet of 16 characters?)... This sounds like (much)
more than a digital watch (do those even exist anymore?)
or even a calculator (only 1 line?).
I feel like you handed us a riddle like the sphynx!
I tried a massive, brooding, indifferent posture to Dougs
posts on this one, but I could only hold the pose for a
few seconds before breaking into a belly laugh appropriate
only for the Buddha or Santa Claus.
- Steve
Just to update fellow FRIAMers.
The most common standard display device in the world
today is the 16x2 character LCD display. The vast
majority of installations use it in 4 bit mode.
On Tue, Feb 5, 2013 at 12:08 AM, Douglas Roberts
<[email protected] <mailto:[email protected]>> wrote:
As a courtesy to our old-fashioned (to put it
politely) FRIAM list members who are still reading
email on their TRS-80 ascii terminals, I will supply
a synopses of the material contained in that
new-fangled url thingie below: the article discusses
a massive, indifferent, brooding silence.
You're welcome.
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--
/Doug Roberts
[email protected] <mailto:[email protected]>/
/http://parrot-farm.net/Second-Cousins/
/
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to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
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Meets Fridays 9a-11:30 at cafe at St. John's College
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