RS-232 Circuit

[Mark van der Eynden]

"Blog the Haggis" <blah@nospam.org> wrote in message news:<bi4gm8$2ei$1@lust.ihug.co.nz>...

"Mark van der Eynden" <mvandere@iprimus.com.au> wrote in message
news:48ed3358.0308211406.b0e51a5@posting.google.com...
You are right, it can be done with a shift register. There was a
circuit in ETI, in the '80s, I think, that used a shift register and a
555 to turn 8 bits into serial. The start and stop bits were hard
wired. Hmmmm. Try looking up the ETI 632 VDU, I seem to vaguely recall
it having a multiturn pot to get the baud rate right. There was two
types of keyboard, the first cost an arm and a leg, the second was
cheaper and used the shift register approach, maybe, it's a bit grey.

Cheers,

Mark, trying to remember too much ancient history.

Hi Mark, yes that's the sort of thing that I'm trying to do. I think it will
be fairly easy to generate the stop bit, all I'll have to do is hard wire a
logic 1 to the serial input and by the time I've transmitted the 8 bits I
should have a register full of them.

At the moment I'm trying to think of some clever (and easy!) way of getting
the start bit. So far the only solution that comes to mind is to add a
flip-flop to the output of the register which I can load a 0 into. Not a
very satisfactory solution but it would work. Maybe I can get the DTR line
triggering the start bit...

-Duncan

Couldn't find any references to it on the weekend. Only had time to
look in a few old books, though. I remember initially thinking there
is no way this circuit could work and spending quite some time trying
to understand how it worked. This was in the days when AY1013s(?) cost
$20 each and the hardware to just encode it could be done for about
$7.

You can use a 74ls165 to encode the 8 bits, you can also use this to
generate the start and stop bits (look at what shift/load does to the
output). It would seem to be a matter of having shift/load low for the
1st and 10th clock pulses.

I'll leave the rest up to you?

Cheers,

Mark

 

[Mike Harding]

On Mon, 25 Aug 2003 09:23:55 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:qefikvolpo93e42rtei1c37a0co6eqg47g@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.

You're quite obsessive too, did you know?

Mike Harding

 

[Rod Speed]

Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:b86jkv0j8ig89ab5uu7ievq382hjlqbtrr@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.

 

[Blog the Haggis]

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bic9eb$7c91k$1@ID-69072.news.uni-berlin.de...

Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:b86jkv0j8ig89ab5uu7ievq382hjlqbtrr@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.

Come on guys, I didn't mean to start a war
I truly appreciated both your advice.

-Duncan

 

[Mike Harding]

On Mon, 25 Aug 2003 16:13:31 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:b86jkv0j8ig89ab5uu7ievq382hjlqbtrr@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.

In fact it's interesting to watch your obsessional behaviour
manifest itself in this childish need to _always_ have the
last word even though that last word is consistently puerile.
Hmmm....

Mike Harding

 

[Rod Speed]

Blog the Haggis <blah@nospam.org> wrote in
message news:bicbbm$krf$1@lust.ihug.co.nz...

Come on guys, I didn't mean to start a war

You wouldnt know what a real war was if one bit you on the arse |-)

I truly appreciated both your advice.

Stoppit at once. Who knows what that sort of thing could lead to |-)

 

[Mike Harding]

On Mon, 25 Aug 2003 16:49:08 +1000, "Blog the Haggis"
<blah@nospam.org> wrote:

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bic9eb$7c91k$1@ID-69072.news.uni-berlin.de...
Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:b86jkv0j8ig89ab5uu7ievq382hjlqbtrr@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.

Come on guys, I didn't mean to start a war

Rod is well known on usenet (and bulletin boards before
that) for being an arrogant bullying psychotic, which is
a shame really because, in some areas, he is quite
knowledgeable. I'm just playing with him at the moment,
to amuse myself - it's childish fun to lure him so easily
along a path he so needs to tread

Mike Harding

PS. Let us know how you go with your RS232 thingy,
but I would still suggest a micro.

 

[Mike Harding]

On Tue, 26 Aug 2003 08:32:48 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:5lvkkv4qto0rah0gai7e9bhutvl6bsdgut@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.

Rod, you have my permission to have the last word in
this thread - in fact I insist you make another response.

Mike Harding

 

[Rod Speed]

Some pathetic excuse for a bullshit artist claiming to be
Mike Harding <mike_harding1@hotmail.com> desperately attempted
to bullshit its way out of its predicament when its nose was rubbed
in yet another of its terminally pig ignorant stupiditys in message
news:bfflkvg5reoitbabqh235kh4d6djanu006@4ax.com...
and fooled absolutely no one at all. As always.

Try harder, fuckwit. You might actually manage to fool someone, sometime.