Counter ICs

[Josef Moellers]

Am 1.7.2011 schrub Richard:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

If you cannot, in no way, tolerate "glitches", i.e. unwanted
intermediate counter values, a gray-code counter is (the only?)
solution: a BCD counter may need to change several bits when progressing
from one count to the next (e.g. all 4 bits need to change when going
from 7 to 8), but since we're dealing with real-world hardware, they
may, in fact, not change simultaneously but in (very fast) succession,
so rather than
0111 -> 1000
you may end up with 0111 -> 0110 -> 0100 -> 0000 -> 1000
Gray code changes only a single bit between values.

However, I'm not sure if a decimal gray code exists.

Also, I know of no standard Gray Code to 7-segment decoders.

Josef
--
These are my personal views and not those of Fujitsu Technology Solutions!
Josef Möllers (Pinguinpfleger bei FTS)
If failure had no penalty success would not be a prize (T. Pratchett)
Company Details: http://de.ts.fujitsu.com/imprint.html

 

[John Fields]

On Fri, 01 Jul 2011 10:23:11 +0100, Richard <none@ntlworld.com> wrote:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

---
Sure.

You could use a binary counter and, with a little glue logic, reset it
when it gets to 1010 and generate a carry if you needed one.

You could also build a state machine using a ROM with an output latch:

(View in Courier)

+--------+
CLK>---|A0 D0|
| |
|A1 D1|
| |
|A1 D1|
| |
|A1 D1|



--
JF

 

[Jasen Betts]

On 2011-06-30, John Fields <jfields@austininstruments.com> wrote:

http://www.technologystudent.com/elec1/count1.htm

not that I'm reccomend that circuit (with a 9V supply) other than as an
experiment as it's using the LEDS outside of their specifications and
they may not last very long, it's better to use one resistor for each LED

---
How so?

Since there's never more than one LED ON at time, a single resistor is
fine.

many leds are spec'd for max 5V reverse bias (I've yet to see a
datasheet with a higher figure) that circuit will give about
6 or 7.

I'm aware that often they can withstand 12V reverse without
damage but I've seem some damaged by less too.

--
⚂⚃ 100% natural

 

[John Fields]

On Fri, 01 Jul 2011 07:11:02 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Fri, 01 Jul 2011 10:23:11 +0100, Richard <none@ntlworld.com> wrote:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

---
Oops... Messed up the last post.

Sure.

You could use a binary counter and, with a little glue logic, reset it
when it gets to 1010 and generate a carry if you needed one.

You could also build a state machine using a ROM with an output latch:

(View in Courier)


.. ROM LATCH
.. +-----+ +-----+
..CLK>-----|A0 D0|--|D0 Q0|---> CARRY OUT
.. | | | |
.. +-------|A1 D1|--|D1 Q1|-------+--[LEDa]-[R]-+
.. | | | | | | |
.. |+------|A2 D2|--|D2 Q2|------+---[LEDb]-[R]-+
.. || | | | | || |
.. ||+-----|A3 D3|--|D3 Q3|-----+----[LEDc]-[R]-+
.. ||| | | | | ||| |
.. |||+----|A4 D4|--|D4 Q4|----+-----[LEDd]-[R]-+
.. |||| | | | | |||| |
.. ||||+---|A5 D5|--|D5 Q5|---+------[LEDe]-[R]-+
.. ||||| | | | | ||||| |
.. |||||+--|A6 D6|--|D6 Q6|--+-------[LEDf]-[R]-+
.. |||||| | | | | |||||| |
.. ||||||+-|A7 D7|--|D7 Q7|-+--------[LEDg]-[R]-+
.. ||||||| +-----+ +-----+ ||||||| |
.. ||||||+------------------+|||||| +V or GND
.. |||||+--------------------+|||||
.. ||||+----------------------+||||
.. |||+------------------------+|||
.. ||+--------------------------+||
.. |+----------------------------+|
.. +------------------------------+

Clocking the latch and generating the lookup table is left as an
exercise for the student.

--
JF

 

[Jasen Betts]

On 2011-07-01, Jon Kirwan <jonk@infinitefactors.org> wrote:

https://estore.ti.com/MSP-EXP430G2-MSP430-LaunchPad-Value-Line-Development-kit-P2031.aspx

Doesn't get cheaper or easier.

Doesn't get cheaper.

signup hage is broken



--
⚂⚃ 100% natural

 

[Jasen Betts]

On 2011-07-01, Josef Moellers <josef.moellers@ts.fujitsu.com> wrote:

However, I'm not sure if a decimal gray code exists.

excess-3 code with xors in the usual places will get you a base-10 gray
code.

Also, I know of no standard Gray Code to 7-segment decoders.

use the same XORs to recover the excess-3 code and go from there to BCD
with some adders.

--
⚂⚃ 100% natural

 

[Jasen Betts]

On 2011-07-01, Jon Kirwan <jonk@infinitefactors.org> wrote:

https://estore.ti.com/MSP-EXP430G2-MSP430-LaunchPad-Value-Line-Development-kit-P2031.aspx

Doesn't get cheaper or easier.

Doesn't get cheaper.

signup page is broken



--
⚂⚃ 100% natural

 

[John Fields]

On 1 Jul 2011 12:18:07 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-06-30, John Fields <jfields@austininstruments.com> wrote:

http://www.technologystudent.com/elec1/count1.htm

not that I'm reccomend that circuit (with a 9V supply) other than as an
experiment as it's using the LEDS outside of their specifications and
they may not last very long, it's better to use one resistor for each LED

---
How so?

Since there's never more than one LED ON at time, a single resistor is
fine.

many leds are spec'd for max 5V reverse bias (I've yet to see a
datasheet with a higher figure) that circuit will give about
6 or 7.

How so?

Since the 4017 outputs are high true, they go positive to light the
LEDs and go to 0V to extinguish them. The anodes of the LEDs must,
therefore, be connected to the counter outputs and their cathodes
connected together and grounded through R3.

Then, since the cathodes never go positive with respect to the anodes,
how can the LEDs ever become reverse-biased?

I'm aware that often they can withstand 12V reverse without
damage but I've seem some damaged by less too.

---
But, there _are_ two errors in the circuit which'll keep it from
working.

1. The RESET switch should be connected between 9V and pin 15 of the
4017, and,

2. pin 16 of the 4017 should be connected directly to 9V.

Not to my liking is ground being switched, instead of 9V, but what are
ya gonna do?


--
JF

 

[Richard]

On 01/07/2011 13:53, John Fields wrote:

On Fri, 01 Jul 2011 07:11:02 -0500, John Fields
jfields@austininstruments.com> wrote:

On Fri, 01 Jul 2011 10:23:11 +0100, Richard<none@ntlworld.com> wrote:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

---
Oops... Messed up the last post.

Sure.

You could use a binary counter and, with a little glue logic, reset it
when it gets to 1010 and generate a carry if you needed one.

You could also build a state machine using a ROM with an output latch:

(View in Courier)


. ROM LATCH
. +-----+ +-----+
.CLK>-----|A0 D0|--|D0 Q0|---> CARRY OUT
. | | | |
. +-------|A1 D1|--|D1 Q1|-------+--[LEDa]-[R]-+
. | | | | | | |
. |+------|A2 D2|--|D2 Q2|------+---[LEDb]-[R]-+
. || | | | | || |
. ||+-----|A3 D3|--|D3 Q3|-----+----[LEDc]-[R]-+
. ||| | | | | ||| |
. |||+----|A4 D4|--|D4 Q4|----+-----[LEDd]-[R]-+
. |||| | | | | |||| |
. ||||+---|A5 D5|--|D5 Q5|---+------[LEDe]-[R]-+
. ||||| | | | | ||||| |
. |||||+--|A6 D6|--|D6 Q6|--+-------[LEDf]-[R]-+
. |||||| | | | | |||||| |
. ||||||+-|A7 D7|--|D7 Q7|-+--------[LEDg]-[R]-+
. ||||||| +-----+ +-----+ ||||||| |
. ||||||+------------------+|||||| +V or GND
. |||||+--------------------+|||||
. ||||+----------------------+||||
. |||+------------------------+|||
. ||+--------------------------+||
. |+----------------------------+|
. +------------------------------+

Clocking the latch and generating the lookup table is left as an
exercise for the student.

I see that you can use your knowledge to derive a scheme to build
counters-with-display.

Just concentrating, for a moment, on what might be considered strictly
commercial or marketing offerings. I mean, where the manufacturer
promotes ICs for the very purpose of the constructing a
counter-with-display and you are purchasing their scheme. It seems that
these offerings (which could be a package of ICs) are:

*BCD counters
*7-segment decoders
*7-segment displays

And I suppose:

*BCD counter + 7-segment decoder in one IC
*BCD counter + 7-segment decoder + LED display in one IC

If we take what ICs which are available as sort of a manufacturer's
scheme, for a counter-with-display, at the moment the above are the only
schemes I have any knowledge of.

But, there must be schemes involving LCDs. Must be. So, what ICs would
we be talking about in that case? What have the manufacturers of the
chips come up with, in their technical and marketing efforts?

Non microprocessor.

 

[Jon Kirwan]

On 1 Jul 2011 13:11:53 GMT, Jasen Betts <jasen@xnet.co.nz>
wrote:

On 2011-07-01, Jon Kirwan <jonk@infinitefactors.org> wrote:

https://estore.ti.com/MSP-EXP430G2-MSP430-LaunchPad-Value-Line-Development-kit-P2031.aspx

Doesn't get cheaper or easier.

Doesn't get cheaper.

signup page is broken

I'm able to use it, it appears. Oh, well. As a backup plan,
TI's store does have a phone number to call and order stuff,
as well. Used it many times when I've had problems with the
web site. (Yeah, I've had them too.)

Jon

 

[John Fields]

On Fri, 01 Jul 2011 16:45:24 +0100, Richard <none@ntlworld.com> wrote:

On 01/07/2011 13:53, John Fields wrote:
On Fri, 01 Jul 2011 07:11:02 -0500, John Fields
jfields@austininstruments.com> wrote:

On Fri, 01 Jul 2011 10:23:11 +0100, Richard<none@ntlworld.com> wrote:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

---
Oops... Messed up the last post.

Sure.

You could use a binary counter and, with a little glue logic, reset it
when it gets to 1010 and generate a carry if you needed one.

You could also build a state machine using a ROM with an output latch:

(View in Courier)


. ROM LATCH
. +-----+ +-----+
.CLK>-----|A0 D0|--|D0 Q0|---> CARRY OUT
. | | | |
. +-------|A1 D1|--|D1 Q1|-------+--[LEDa]-[R]-+
. | | | | | | |
. |+------|A2 D2|--|D2 Q2|------+---[LEDb]-[R]-+
. || | | | | || |
. ||+-----|A3 D3|--|D3 Q3|-----+----[LEDc]-[R]-+
. ||| | | | | ||| |
. |||+----|A4 D4|--|D4 Q4|----+-----[LEDd]-[R]-+
. |||| | | | | |||| |
. ||||+---|A5 D5|--|D5 Q5|---+------[LEDe]-[R]-+
. ||||| | | | | ||||| |
. |||||+--|A6 D6|--|D6 Q6|--+-------[LEDf]-[R]-+
. |||||| | | | | |||||| |
. ||||||+-|A7 D7|--|D7 Q7|-+--------[LEDg]-[R]-+
. ||||||| +-----+ +-----+ ||||||| |
. ||||||+------------------+|||||| +V or GND
. |||||+--------------------+|||||
. ||||+----------------------+||||
. |||+------------------------+|||
. ||+--------------------------+||
. |+----------------------------+|
. +------------------------------+

Clocking the latch and generating the lookup table is left as an
exercise for the student.


I see that you can use your knowledge to derive a scheme to build
counters-with-display.

Just concentrating, for a moment, on what might be considered strictly
commercial or marketing offerings. I mean, where the manufacturer
promotes ICs for the very purpose of the constructing a
counter-with-display and you are purchasing their scheme. It seems that
these offerings (which could be a package of ICs) are:

*BCD counters
*7-segment decoders
*7-segment displays

And I suppose:

*BCD counter + 7-segment decoder in one IC
*BCD counter + 7-segment decoder + LED display in one IC

If we take what ICs which are available as sort of a manufacturer's
scheme, for a counter-with-display, at the moment the above are the only
schemes I have any knowledge of.

But, there must be schemes involving LCDs. Must be. So, what ICs would
we be talking about in that case? What have the manufacturers of the
chips come up with, in their technical and marketing efforts?

---
Can't help you much there, but take a look at the 4511 and go to:

http://www.national.com/cat/index.cgi?i=i//23

--
JF

 

[Richard]

On 01/07/2011 18:53, John Fields wrote:

On Fri, 01 Jul 2011 16:45:24 +0100, Richard<none@ntlworld.com> wrote:

On 01/07/2011 13:53, John Fields wrote:
On Fri, 01 Jul 2011 07:11:02 -0500, John Fields
jfields@austininstruments.com> wrote:

On Fri, 01 Jul 2011 10:23:11 +0100, Richard<none@ntlworld.com> wrote:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

---
Oops... Messed up the last post.

Sure.

You could use a binary counter and, with a little glue logic, reset it
when it gets to 1010 and generate a carry if you needed one.

You could also build a state machine using a ROM with an output latch:

(View in Courier)


. ROM LATCH
. +-----+ +-----+
.CLK>-----|A0 D0|--|D0 Q0|---> CARRY OUT
. | | | |
. +-------|A1 D1|--|D1 Q1|-------+--[LEDa]-[R]-+
. | | | | | | |
. |+------|A2 D2|--|D2 Q2|------+---[LEDb]-[R]-+
. || | | | | || |
. ||+-----|A3 D3|--|D3 Q3|-----+----[LEDc]-[R]-+
. ||| | | | | ||| |
. |||+----|A4 D4|--|D4 Q4|----+-----[LEDd]-[R]-+
. |||| | | | | |||| |
. ||||+---|A5 D5|--|D5 Q5|---+------[LEDe]-[R]-+
. ||||| | | | | ||||| |
. |||||+--|A6 D6|--|D6 Q6|--+-------[LEDf]-[R]-+
. |||||| | | | | |||||| |
. ||||||+-|A7 D7|--|D7 Q7|-+--------[LEDg]-[R]-+
. ||||||| +-----+ +-----+ ||||||| |
. ||||||+------------------+|||||| +V or GND
. |||||+--------------------+|||||
. ||||+----------------------+||||
. |||+------------------------+|||
. ||+--------------------------+||
. |+----------------------------+|
. +------------------------------+

Clocking the latch and generating the lookup table is left as an
exercise for the student.


I see that you can use your knowledge to derive a scheme to build
counters-with-display.

Just concentrating, for a moment, on what might be considered strictly
commercial or marketing offerings. I mean, where the manufacturer
promotes ICs for the very purpose of the constructing a
counter-with-display and you are purchasing their scheme. It seems that
these offerings (which could be a package of ICs) are:

*BCD counters
*7-segment decoders
*7-segment displays

And I suppose:

*BCD counter + 7-segment decoder in one IC
*BCD counter + 7-segment decoder + LED display in one IC

If we take what ICs which are available as sort of a manufacturer's
scheme, for a counter-with-display, at the moment the above are the only
schemes I have any knowledge of.

But, there must be schemes involving LCDs. Must be. So, what ICs would
we be talking about in that case? What have the manufacturers of the
chips come up with, in their technical and marketing efforts?

---
Can't help you much there, but take a look at the 4511 and go to:

http://www.national.com/cat/index.cgi?i=i//23

I see that the BCD - decoder - 7-segment scheme (more in the sense of
product scheme) was used for LCDs as here:

http://focus.ti.com/lit/ds/symlink/cd4056b.pdf

I guess any BCD counter might have sufficed, probably TI made their own.

 

[krw@att.bizzzzzzzzzzzz]

On Fri, 01 Jul 2011 10:47:26 +0200, Josef Moellers
<josef.moellers@ts.fujitsu.com> wrote:

Am 1.7.2011 schrub Richard:


* I cannot understand why, when you can drive a digit display with 4
bits (only 4 bits required to get up to a count of 10), we have a decade
counter with 10 bits.


While on my way to the morning coffee break, I thought about the
following: one could even construct a decimal counter which counted in
7-segment code! Not that I know how, because it's been ~20 years that I
last used these kind of things.
On practice, this would be a state machine that repeatedly went through
10 states and, when wrapping around, would also output a "carry" signal.

Any takers? ;-)

Easy 'nuff. Take a 7-bit register and a 128 x 7 ROM. Connect the Register's
Q outputs to the address lines of the ROM and the outputs of the ROM feeding
back the D inputs of the register. At the address of the *current* count
(7-segment encoded) put the value of the *next* 7-segment code. Program all
other locations to the value of the '0' code (or choose another). Add the
clock and you're done.

Or you could do 20 lines of VHDL, or so (same thing).

SevenSegCounter: process (Clk, Reset) -- a
begin -- ----
if Reset = 1 -- abcdefg -- f/ g /b
then Output <= "1111110" -- /---/
elsif rising_edge(Clk) -- e/ /c
and CarryIn = '1' -- /---/
then -- C -- d
case Output is -- yabcdefg --
when "1111110" => "01101101"; -- 0=>1
when "0110000" => "01101101"; -- 1=>2
when "1101101" => "01111001"; -- 2=>3
when "1111001" => "01110011"; -- 3=>4
when "1110011" => "01011011"; -- 4=>5
when "1011011" => "01011111"; -- 5=>6
when "1011111" => "01110000"; -- 6=>7
when "1110000" => "01111111"; -- 7=>8
when "1111111" => "11111011"; -- 8=>9
when "1111011" => "01101101"; -- 9=>0
when others => "01111110"; -- Catchall => 0
end case;
end if;
end process SevenSegCounter;

-- The left bit of output is the carry out
-- Disclaimer-1: not checked for errors
-- Disclaimer-2: I have *no* idea why anyone would want to do this

 

[krw@att.bizzzzzzzzzzzz]

On Fri, 01 Jul 2011 11:49:32 +0200, Josef Moellers
<josef.moellers@ts.fujitsu.com> wrote:

Am 1.7.2011 schrub Richard:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

If you cannot, in no way, tolerate "glitches", i.e. unwanted
intermediate counter values, a gray-code counter is (the only?)
solution: a BCD counter may need to change several bits when progressing
from one count to the next (e.g. all 4 bits need to change when going
from 7 to 8), but since we're dealing with real-world hardware, they
may, in fact, not change simultaneously but in (very fast) succession,
so rather than
0111 -> 1000
you may end up with 0111 -> 0110 -> 0100 -> 0000 -> 1000
Gray code changes only a single bit between values.

A synchronous counter won't have transition glitches. Well, any glitches
won't be wider than the delta between propagation delays (which is usually
less than the transition time).

Designs should be transition glitch tolerant, in any case. I don't remember
the last time I used a ripple counter and I *sure* don't design asynchronous
logic.

However, I'm not sure if a decimal gray code exists.

Also, I know of no standard Gray Code to 7-segment decoders.

For good reason. They're never necessary. Do you really care if an 7-segment
display shows the wrong value for 10ps? ;-)

 

[krw@att.bizzzzzzzzzzzz]

On Fri, 01 Jul 2011 16:45:24 +0100, Richard <none@ntlworld.com> wrote:

On 01/07/2011 13:53, John Fields wrote:
On Fri, 01 Jul 2011 07:11:02 -0500, John Fields
jfields@austininstruments.com> wrote:

On Fri, 01 Jul 2011 10:23:11 +0100, Richard<none@ntlworld.com> wrote:

On 01/07/2011 09:29, Richard wrote:
Some more questions about making counters using counter ICs

If you want to make a counter, you can choose to employ 7-segment LED
displays to show digits. It seems that if you go that way you are
practically tied to counters offering BCD outputs. Because you have BCD
to 7-segment display decoders ready-available. Not that you could not
use counters with 1in10 outputs, but you would then need to devise your
own decoder.

Now, we also have fully-decoded counters or one-hot code output counters
of which the 4017 IC is an example. Same as 1in10 counters.

Question is: Do folks build counters with one-hot code counters? I'm
receiving an impression that although counters, you would not build a
counter-with-display with them. But, I think I could be getting the
wrong impression here. And, if you do use them for building a
counter-with-display, what displays do you use? Apart from Dekatrons. :c)

Also, ignoring microprocessors for the moment, what is the modern set-up
for counter-with-display? In other words is using 7-segment LED displays
"old hat"? Or still in vogue.

Aaah, maybe I'm on the right track and fully decoded counters like 4017
would not be used in counters-with-display:

"Decade counter

A decade counter is one that counts in decimal digits, rather than
binary. A decimal counter may have each digit binary encoded (that is,
it may count in binary-coded decimal, as the 7490 integrated circuit
did) or other binary encodings (such as the bi-quinary encoding of the
7490 integrated circuit). Alternatively, it may have a "fully decoded"
or one-hot output code in which each output goes high in turn; the 4017
was such a circuit. The latter type of circuit finds applications in
multiplexers and demultiplexers, or wherever a scanning type of
behaviour is useful. Similar counters with different numbers of outputs
are also common.

The decade counter is also known as a mod-10 counter."

http://www.tititudorancea.com/z/counter.htm

So, at the moment I'm only seeing BCD output counters that are in the
ballpark for counter-with-display. But, there must be other non BCD
counters suitable?

---
Oops... Messed up the last post.

Sure.

You could use a binary counter and, with a little glue logic, reset it
when it gets to 1010 and generate a carry if you needed one.

You could also build a state machine using a ROM with an output latch:

(View in Courier)


. ROM LATCH
. +-----+ +-----+
.CLK>-----|A0 D0|--|D0 Q0|---> CARRY OUT
. | | | |
. +-------|A1 D1|--|D1 Q1|-------+--[LEDa]-[R]-+
. | | | | | | |
. |+------|A2 D2|--|D2 Q2|------+---[LEDb]-[R]-+
. || | | | | || |
. ||+-----|A3 D3|--|D3 Q3|-----+----[LEDc]-[R]-+
. ||| | | | | ||| |
. |||+----|A4 D4|--|D4 Q4|----+-----[LEDd]-[R]-+
. |||| | | | | |||| |
. ||||+---|A5 D5|--|D5 Q5|---+------[LEDe]-[R]-+
. ||||| | | | | ||||| |
. |||||+--|A6 D6|--|D6 Q6|--+-------[LEDf]-[R]-+
. |||||| | | | | |||||| |
. ||||||+-|A7 D7|--|D7 Q7|-+--------[LEDg]-[R]-+
. ||||||| +-----+ +-----+ ||||||| |
. ||||||+------------------+|||||| +V or GND
. |||||+--------------------+|||||
. ||||+----------------------+||||
. |||+------------------------+|||
. ||+--------------------------+||
. |+----------------------------+|
. +------------------------------+

Clocking the latch and generating the lookup table is left as an
exercise for the student.


I see that you can use your knowledge to derive a scheme to build
counters-with-display.

There is no need, or they would exist. In fact they did exist. HP made a
series of LEDs with a counter built in. They were *expensive*, though.

Just concentrating, for a moment, on what might be considered strictly
commercial or marketing offerings. I mean, where the manufacturer
promotes ICs for the very purpose of the constructing a
counter-with-display and you are purchasing their scheme. It seems that
these offerings (which could be a package of ICs) are:

*BCD counters
*7-segment decoders
*7-segment displays

And I suppose:

*BCD counter + 7-segment decoder in one IC
*BCD counter + 7-segment decoder + LED display in one IC

If we take what ICs which are available as sort of a manufacturer's
scheme, for a counter-with-display, at the moment the above are the only
schemes I have any knowledge of.

But, there must be schemes involving LCDs. Must be. So, what ICs would
we be talking about in that case? What have the manufacturers of the
chips come up with, in their technical and marketing efforts?

There are all sorts of LCD controllers but there wouldn't be any point in a
standard product like you propose. The market is too limited.

Non microprocessor.

Why?

 

[Richard]

On 02/07/2011 00:31, krw@att.bizzzzzzzzzzzz wrote:

Just concentrating, for a moment, on what might be considered strictly
commercial or marketing offerings. I mean, where the manufacturer
promotes ICs for the very purpose of the constructing a
counter-with-display and you are purchasing their scheme. It seems that
these offerings (which could be a package of ICs) are:

*BCD counters
*7-segment decoders
*7-segment displays

And I suppose:

*BCD counter + 7-segment decoder in one IC
*BCD counter + 7-segment decoder + LED display in one IC

If we take what ICs which are available as sort of a manufacturer's
scheme, for a counter-with-display, at the moment the above are the only
schemes I have any knowledge of.

But, there must be schemes involving LCDs. Must be. So, what ICs would
we be talking about in that case? What have the manufacturers of the
chips come up with, in their technical and marketing efforts?

There are all sorts of LCD controllers but there wouldn't be any point in a
standard product like you propose. The market is too limited.

Non microprocessor.

Why?

I'm just now learning about counters-with-display. Really limited to ICs
associated with counting and (7-segment) displays. Not just counting.

Okay, so I see that it's more or less a matter of the display technology
which is LED or LCD. Has been for a while and still is.

Either way, counter-with-display involves(more or less) decade counters
outputting BCD, BCD to 7-segment decoders, LED or LCD 7-segment displays.

Other counters, such as one-hot code counters are not manufacturer for
counter-with-display purposes in mind.

Of course with ingenuity, you can make counter-with-display from a
variety of ICs, you can implement your own peculiar technical schemes.
Which is probably what some do.

But as to "product" schemes of manufacturers, it seems BCD counters are
the regular offering, with associated decoder and 7-segment display.

That is my understanding of the situation.

Not entirely sure where binary counter and 7-segment display would
figure, if people do that.

As to microprocessor. Yes, that is where I ought to be heading towards
getting to grips with.

 

[Jasen Betts]

On 2011-07-01, John Fields <jfields@austininstruments.com> wrote:

On 1 Jul 2011 12:18:07 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-06-30, John Fields <jfields@austininstruments.com> wrote:

http://www.technologystudent.com/elec1/count1.htm

not that I'm reccomend that circuit (with a 9V supply) other than as an
experiment as it's using the LEDS outside of their specifications and
they may not last very long, it's better to use one resistor for each LED

How so?

Since there's never more than one LED ON at time, a single resistor is
fine.

many leds are spec'd for max 5V reverse bias (I've yet to see a
datasheet with a higher figure) that circuit will give about
6 or 7.

How so?

Since the 4017 outputs are high true, they go positive to light the
LEDs and go to 0V to extinguish them. The anodes of the LEDs must,
therefore, be connected to the counter outputs and their cathodes
connected together and grounded through R3.

grounded?

R3 is the current limit resistor and drops atleast 6V

Then, since the cathodes never go positive with respect to the anodes,
how can the LEDs ever become reverse-biased?

All of the cathodes are at around 6V, 9 of he anodes are at around 0V

But, there _are_ two errors in the circuit which'll keep it from
working.

1. The RESET switch should be connected between 9V and pin 15 of the
4017, and,

2. pin 16 of the 4017 should be connected directly to 9V.

Not to my liking is ground being switched, instead of 9V, but what are
ya gonna do?

I didn't spot that mistake, but on reexamineing it the animation of
the schematic looks almost right for the circuit as drawn. The 4017
is being powered through the clock input (I've done this by accident
before), but to may way of thinking the red on the clock wire should
coincide with the LED illuminating.




--
⚂⚃ 100% natural

 

[John Fields]

On 2 Jul 2011 10:49:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-07-01, John Fields <jfields@austininstruments.com> wrote:
On 1 Jul 2011 12:18:07 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-06-30, John Fields <jfields@austininstruments.com> wrote:

http://www.technologystudent.com/elec1/count1.htm

not that I'm reccomend that circuit (with a 9V supply) other than as an
experiment as it's using the LEDS outside of their specifications and
they may not last very long, it's better to use one resistor for each LED

How so?

Since there's never more than one LED ON at time, a single resistor is
fine.

many leds are spec'd for max 5V reverse bias (I've yet to see a
datasheet with a higher figure) that circuit will give about
6 or 7.

How so?

Since the 4017 outputs are high true, they go positive to light the
LEDs and go to 0V to extinguish them. The anodes of the LEDs must,
therefore, be connected to the counter outputs and their cathodes
connected together and grounded through R3.

grounded?

R3 is the current limit resistor and drops atleast 6V

Then, since the cathodes never go positive with respect to the anodes,
how can the LEDs ever become reverse-biased?

All of the cathodes are at around 6V, 9 of he anodes are at around 0V

---
Heh!

Completely missed that; good catch!

--
JF

 

[John Fields]

On 2 Jul 2011 10:49:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-07-01, John Fields <jfields@austininstruments.com> wrote:
On 1 Jul 2011 12:18:07 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-06-30, John Fields <jfields@austininstruments.com> wrote:

http://www.technologystudent.com/elec1/count1.htm

not that I'm reccomend that circuit (with a 9V supply) other than as an
experiment as it's using the LEDS outside of their specifications and
they may not last very long, it's better to use one resistor for each LED

How so?

Since there's never more than one LED ON at time, a single resistor is
fine.

many leds are spec'd for max 5V reverse bias (I've yet to see a
datasheet with a higher figure) that circuit will give about
6 or 7.

How so?

Since the 4017 outputs are high true, they go positive to light the
LEDs and go to 0V to extinguish them. The anodes of the LEDs must,
therefore, be connected to the counter outputs and their cathodes
connected together and grounded through R3.

grounded?

R3 is the current limit resistor and drops atleast 6V

Then, since the cathodes never go positive with respect to the anodes,
how can the LEDs ever become reverse-biased?

All of the cathodes are at around 6V, 9 of he anodes are at around 0V

But, there _are_ two errors in the circuit which'll keep it from
working.

1. The RESET switch should be connected between 9V and pin 15 of the
4017, and,

2. pin 16 of the 4017 should be connected directly to 9V.

Not to my liking is ground being switched, instead of 9V, but what are
ya gonna do?

I didn't spot that mistake, but on reexamineing it the animation of
the schematic looks almost right for the circuit as drawn. The 4017
is being powered through the clock input (I've done this by accident
before), but to may way of thinking the red on the clock wire should
coincide with the LED illuminating.

---
Yeah, you're right; the count changes on the _rising_ edge of the
clock.

That is, if there's enough charge left in the chip to ride out the
clock's low time and hold Vcc up until the next clock comes along.

Plus, take a look at pin 1 of the 555!

--
JF

 

[krw@att.bizzzzzzzzzzzz]

On Sat, 02 Jul 2011 08:03:27 +0100, Richard <none@ntlworld.com> wrote:

On 02/07/2011 00:31, krw@att.bizzzzzzzzzzzz wrote:

Just concentrating, for a moment, on what might be considered strictly
commercial or marketing offerings. I mean, where the manufacturer
promotes ICs for the very purpose of the constructing a
counter-with-display and you are purchasing their scheme. It seems that
these offerings (which could be a package of ICs) are:

*BCD counters
*7-segment decoders
*7-segment displays

And I suppose:

*BCD counter + 7-segment decoder in one IC
*BCD counter + 7-segment decoder + LED display in one IC

If we take what ICs which are available as sort of a manufacturer's
scheme, for a counter-with-display, at the moment the above are the only
schemes I have any knowledge of.

But, there must be schemes involving LCDs. Must be. So, what ICs would
we be talking about in that case? What have the manufacturers of the
chips come up with, in their technical and marketing efforts?

There are all sorts of LCD controllers but there wouldn't be any point in a
standard product like you propose. The market is too limited.

Non microprocessor.

Why?

I'm just now learning about counters-with-display. Really limited to ICs
associated with counting and (7-segment) displays. Not just counting.

Why? It's a learning exercise to do a counter-AND-display, but
counter-with-display isn't all that much use, today. That's why you don't see
them anymore.

Okay, so I see that it's more or less a matter of the display technology
which is LED or LCD. Has been for a while and still is.

LED vs. LCD isn't the point.

Either way, counter-with-display involves(more or less) decade counters
outputting BCD, BCD to 7-segment decoders, LED or LCD 7-segment displays.

Which isn't all that interesting, marketing wise.

Other counters, such as one-hot code counters are not manufacturer for
counter-with-display purposes in mind.

Why would *anyone* do such a thing? The fact is that counter-with-display
isn't interesting. Thirty years ago, perhaps.

Of course with ingenuity, you can make counter-with-display from a
variety of ICs, you can implement your own peculiar technical schemes.
Which is probably what some do.

Sure, they use a microcontroller (or FPGA, like I'm doing now). ;-)

But as to "product" schemes of manufacturers, it seems BCD counters are
the regular offering, with associated decoder and 7-segment display.

Why add gates unnecessarily?

That is my understanding of the situation.

Not entirely sure where binary counter and 7-segment display would
figure, if people do that.

Sure: '0123456789AbCdEF'

As to microprocessor. Yes, that is where I ought to be heading towards
getting to grips with.

If you're looking to learn logic design, there is nothing wrong with playing
with counters and displays. We all started there (or before , at some point
in our careers. Any sort of saleable product isn't going to use such things
(counters integrated with the display).