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--- In Electronics_101@..., "lcdpublishing"
<lcdpublishing@...> wrote:

Thanks guys, I will double check the data sheet again to see if I
can "Get it". If not, I guess the next best thing is to drop it in a
socket and give it a try. I have a working module setup right now
with a cpe part, so swaping the chip for a test is pretty easy. I
just didn't want to let the smoke out if there was more to this part
number suffix.

CHris

Looks to me like the MAX232N is a Texas Instruments part while the
MAX232CPE is a Maxim part. At least that't the way I found the
datasheets.

No matter, both use 1.0 ufd capacitors. Too bad, the MAX232A uses 0.1
ufd which are much smaller.

I prefer the MAX233 because it doesn't require any charge pump
capacitors. It still requires a decoupling capacitor.

Richard

On Mon, 01 May 2006 18:39:33 +0200, rtstofer <rstofer@...> wrote:

Among other things, if you build a software state machine to track the

changes, debouncing will be automatic. Sure, you may bobble between A

is high, B is high back and forth with A is low, B is high (or A is

high, B is low) (in other words both sides of the transition) but it

doesn't matter because only one line is changing states - you wont go

from A is high, B is high to A is low, B is low.


You aren't transitioning far enough to upset the count or miss a

detent position. But you can detect the difference between increase

and decrease.


Richard

Yes, even I managed to make the software for a encoder of this type work, and that says something!
Good thinking really that quadrature stuff...

ST

--- In Electronics_101@..., "lcdpublishing"
<lcdpublishing@...> wrote:

--- In Electronics_101@..., "rtstofer" <rstofer@> wrote:

Should I just count the 24 detent pulses?
OR
Should I count the 96 pulses per revolution?

A link to a datasheet would help...

Richard

This link should take you to the datasheet (I hope)


E/EC12E.PDF

OK, the device has quadrature outputs. This produces 4 transitions
between detents. The reason for quadrature is to provide an
indication of the direction of rotation. On page 194 you will see a
state diagram.

Starting from the left indicated detent location the pattern is: A
goes low then B goes low then A goes high then B goes high.

In the other direction the transitions are: B goes low then A goes low
then B goes high then A goes high.

From the pattern of transitions, direction can be determined.

Among other things, if you build a software state machine to track the
changes, debouncing will be automatic. Sure, you may bobble between A
is high, B is high back and forth with A is low, B is high (or A is
high, B is low) (in other words both sides of the transition) but it
doesn't matter because only one line is changing states - you wont go
from A is high, B is high to A is low, B is low.

You aren't transitioning far enough to upset the count or miss a
detent position. But you can detect the difference between increase
and decrease.

Richard

Thanks guys, I will double check the data sheet again to see if I
can "Get it". If not, I guess the next best thing is to drop it in a
socket and give it a try. I have a working module setup right now
with a cpe part, so swaping the chip for a test is pretty easy. I
just didn't want to let the smoke out if there was more to this part
number suffix.

CHris

--- HARI CHARAN <sharicharan@...> wrote:

Is there any body to say me or send me to know abt
the basics of
electronics?

Go for "Integrated Electronics" by Millman & Halkias.
Best book in the subject.



__________________________________________________________
Yahoo! India Answers: Share what you know. Learn something new.

most often this suffix is the package and temperature range.
As long as it fits it should be fine.

But beware, there were -R versions of ICs that were mirrored upside down!

Ideally check the datasheet, but different manufacturers may use different suffixes.
CPE should be consumer temp range, and plastic DIP, i think, for maxim.

ST

On Monday 01 May 2006 10:48 am, lcdpublishing wrote:

Roy, I will do when I get the cable in that I plan on using for
this. By chance, can you give me a hint as to what sort of good and
bad things I should be looking for?

Nope, I just know that the signal _will_ change and that it might be
instructive to see how it changes...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

Roy, I will do when I get the cable in that I plan on using for
this. By chance, can you give me a hint as to what sort of good and
bad things I should be looking for?

Right now, my technique on the scope is more or less, if I see two
horizontal lines - spaced apart at the voltage and duration I think
they should be - I am happy.

Chris



--- In Electronics_101@..., "Roy J. Tellason"
<rtellason@...> wrote:

On Monday 01 May 2006 09:02 am, lcdpublishing wrote:

It does appear that 20 feet of cable will work for SPI. The

length

is approximate, but I think it is close to 20'.

<...>

In reality, I would have been very surprised had it worked!

When

I was first working out some serial communications software

about 20

years ago, I used all short cables and PC-PC for testing.

Then to

find the distance limitation with RS232, I had four, 1000 foot
spools of cable on hand. I started out with one spool, then

two,

then on the third one it failed. At the time I had no idea

why,

but I was aware that having the cable on the spool was

a "worst case"

situation.

Today's test I am going to cut off about a 25 foot section of

the

cable I tried for SPI, and see if that works. If not, I will

keep

cutting it down till it does.

--- In Electronics_101@..., "Roy J. Tellason"

<rtellason@> wrote:

On Sunday 30 April 2006 04:55 pm, lcdpublishing wrote:

Well, I know for sure what won't work!

I had a 100' spool of 24 gauge solid core wire handy with

both

ends of the cable exposed. I stripped off some conductors,

spliced it

into the bread board circuit for the SPI wires. No-go,

so, now I

know!

100 feet - too long for SPI ;-)

A bunch of wire on a spool is also going to have some
inductance, there,

much more so than just a wire run to somewhere...

You might find it informative to put a scope on that signal,

without the wire

and then with it, both at the source end and at the other end as

well...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that

can

be killed but can't be tamed. --Robert A. Heinlein, "The Puppet

Masters"

-
Information is more dangerous than cannon to a society ruled by

lies. --James

M Dakin

--- In Electronics_101@..., "rtstofer" <rstofer@...> wrote:

Should I just count the 24 detent pulses?
OR
Should I count the 96 pulses per revolution?

A link to a datasheet would help...

Richard

This link should take you to the datasheet (I hope)


E/EC12E.PDF

Hi Guys,

I have a number of MAX232 chips on hand. Some are marked MAX232cpe
and some are marked MAX232n. I tried to gather up what the
differences are from the datasheet, but all that did was confuse me
more. My primary concern is if they both get wired up the same, I am
not too worried about if they are "industrial" or "medical" grade etc.

If anyone knows the differences, I sure would appreciate the info!

THanks again!

Chris

On Monday 01 May 2006 09:02 am, lcdpublishing wrote:

It does appear that 20 feet of cable will work for SPI. The length
is approximate, but I think it is close to 20'.

<...>

In reality, I would have been very surprised had it worked! When
I was first working out some serial communications software about 20
years ago, I used all short cables and PC-PC for testing. Then to
find the distance limitation with RS232, I had four, 1000 foot
spools of cable on hand. I started out with one spool, then two,
then on the third one it failed. At the time I had no idea why,
but I was aware that having the cable on the spool was a "worst case"
situation.

Today's test I am going to cut off about a 25 foot section of the
cable I tried for SPI, and see if that works. If not, I will keep
cutting it down till it does.

--- In Electronics_101@..., "Roy J. Tellason"

<rtellason@> wrote:

On Sunday 30 April 2006 04:55 pm, lcdpublishing wrote:

Well, I know for sure what won't work!

I had a 100' spool of 24 gauge solid core wire handy with both
ends of the cable exposed. I stripped off some conductors, spliced it
into the bread board circuit for the SPI wires. No-go, so, now I
know!

100 feet - too long for SPI ;-)

A bunch of wire on a spool is also going to have some
inductance, there,

much more so than just a wire run to somewhere...

You might find it informative to put a scope on that signal, without the wire
and then with it, both at the source end and at the other end as well...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

Should I just count the 24 detent pulses?
OR
Should I count the 96 pulses per revolution?

A link to a datasheet would help...

Richard

It does appear that 20 feet of cable will work for SPI. The length
is approximate, but I think it is close to 20'.

The speed at which I am communicating at though is a bit confusing
based on the documentation I am working with in the BASCOM manual.
If I am interpreting it correctly, I am communicating at 1/16 clock
speed. So 18.432 Mhz xtal 18,432,000 / 16 = 1,152,000 bits per
second.

If I understand everything correctly, this is very good news for
this project! Things just got a lot faster and better.

CHris



--- In Electronics_101@..., "lcdpublishing"
<lcdpublishing@...> wrote:

HI ROy,

In reality, I would have been very surprised had it worked! When

I

was first working out some serial communications software about 20
years ago, I used all short cables and PC-PC for testing. Then to
find the distance limitation with RS232, I had four, 1000 foot
spools of cable on hand. I started out with one spool, then two,
then on the third one it failed. At the time I had no idea why,

but

I was aware that having the cable on the spool was a "worst case"
situation.

Today's test I am going to cut off about a 25 foot section of the
cable I tried for SPI, and see if that works. If not, I will keep
cutting it down till it does.




--- In Electronics_101@..., "Roy J. Tellason"
<rtellason@> wrote:

On Sunday 30 April 2006 04:55 pm, lcdpublishing wrote:

Well, I know for sure what won't work!

I had a 100' spool of 24 gauge solid core wire handy with both

ends of

the cable exposed. I stripped off some conductors, spliced it

into the

bread board circuit for the SPI wires. No-go, so, now I know!

100 feet - too long for SPI ;-)

A bunch of wire on a spool is also going to have some

inductance,

there,

much more so than just a wire run to somewhere...

--
Member of the toughest, meanest, deadliest, most unrelenting --

and

ablest -- form of life in this section of space, a critter that

can

be killed but can't be tamed. --Robert A. Heinlein, "The Puppet

Masters"

-
Information is more dangerous than cannon to a society ruled by

lies. --James

M Dakin

HI Guys,

Yesterday I was experimenting with my AVR software and working with
the different controls I will have on my operator panel. I got
everything working good in the test rig but found something unusual
with the rotary encoder switches.

The encoder switches I have are called 24 PPR and have 24 detents.
However, when decoding them in software, I quickly noticed they
output 4 pulses per detent which makes them 96 "steps" per
revolution.

I know once before I got myself all messed up with encoder switches
(I have only used them once before). I guess what I am asking is
this...

Should I just count the 24 detent pulses?
OR
Should I count the 96 pulses per revolution?

If I work with the 96 PPR count, I can see some problems with things
getting a little bit confusing when you release the knob between two
detents and it moves itself into the detent position.

To me, it would just make more sense to have 24 detents per rev. and
24 counts per revolution. But, being cheap these days, it seems as
though I am "throwing away 75% of the steps" :-)

Chris (Confused from a tough weekend of programming)

HI ROy,

In reality, I would have been very surprised had it worked! When I
was first working out some serial communications software about 20
years ago, I used all short cables and PC-PC for testing. Then to
find the distance limitation with RS232, I had four, 1000 foot
spools of cable on hand. I started out with one spool, then two,
then on the third one it failed. At the time I had no idea why, but
I was aware that having the cable on the spool was a "worst case"
situation.

Today's test I am going to cut off about a 25 foot section of the
cable I tried for SPI, and see if that works. If not, I will keep
cutting it down till it does.




--- In Electronics_101@..., "Roy J. Tellason"
<rtellason@...> wrote:

On Sunday 30 April 2006 04:55 pm, lcdpublishing wrote:

Well, I know for sure what won't work!

I had a 100' spool of 24 gauge solid core wire handy with both

ends of

the cable exposed. I stripped off some conductors, spliced it

into the

bread board circuit for the SPI wires. No-go, so, now I know!

100 feet - too long for SPI ;-)

A bunch of wire on a spool is also going to have some inductance,

there,

much more so than just a wire run to somewhere...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that

can

be killed but can't be tamed. --Robert A. Heinlein, "The Puppet

Masters"

-
Information is more dangerous than cannon to a society ruled by

lies. --James

M Dakin

The biggest mistake newbies make is an unintentional lack of tact caused by excitement at having found a bunch of people who share their interest in electronics.

How to avoid this and increase your chances of getting help on Electronics_101 list:

1. Say please, and thank you. If people feel like you are demanding help, and not likely to be appreciative, they are a lot less likely to help.

2. Use a subject line that makes sense. Many of us have been here for a long time and are on many lists, and may scan subject lines and only read those that either interest us or cover something we think we can help with. Subject lines like "Help me", or "Strange thing" aren't likely to get as many people reading your message.

3. Be specific with your questions, and show us you've done your own work. Don't ask us to teach you everything there is to know about the subject, books are written about even narrow fields in electronics. "How do I use a transistor" is way too broad.

4. Use Google first. Search the internet, look in the Links section of this list and search the archives of this list, too.

5. Don't ask us to do your homework for you. Many of us have gone through school and can pretty quickly figure that out. Hey, if we weren't that smart, you wouldn't be asking us for help.

6. And from the other side of the coin, when someone new joins the list please keep in mind that English is a second language to most of the world. Please write things out, many of us will ignore messages written in "texting language". Example: "i nd hlp 4 my projct, r u abl 2 hlp?" And as the joke goes, England and America are "separated by a common language". A recent study indicates that people are convinced they can read accurately the emotions behind an email about 90% of the time, when in fact they are only 50% accurate.

Steve Greenfield
moderator Electronics_101

On Sunday 30 April 2006 04:55 pm, lcdpublishing wrote:

Well, I know for sure what won't work!

I had a 100' spool of 24 gauge solid core wire handy with both ends of
the cable exposed. I stripped off some conductors, spliced it into the
bread board circuit for the SPI wires. No-go, so, now I know!

100 feet - too long for SPI ;-)

A bunch of wire on a spool is also going to have some inductance, there,
much more so than just a wire run to somewhere...

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

Crownhill in Malta used to advertise their Dashmaster
as being able to deal with most West European makes of
vehicles. It was expensive (about GBP500) and I don't
know if they still sell it.

signalsnatcher

Current location - Wollongong, the steel city, Australia

Specialising in - improvised communication networks, cabled and wireless data transmission, telemetry, remote control and associated technologies.



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