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Richard
Guest
Thu Jun 30, 2011 9:29 am
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
Jon Kirwan
Guest
Thu Jun 30, 2011 10:58 am
On Thu, 30 Jun 2011 10:29:37 +0100, Richard
<none_at_ntlworld.com> wrote:
Quote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
Examine this java-coded display of one:
http://www.falstad.com/circuit/e-johnsonctr.html
It's a 5-bit ring, but the output of the last bit is inverted
and fed back so it takes two loops through to repeat itself
completely.
Jon
Jasen Betts
Guest
Thu Jun 30, 2011 11:30 am
On 2011-06-30, Richard <none_at_ntlworld.com> wrote:
Quote:
Hi, you've found a data-sheet that's a really good start.
Quote:
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
actually it's a 5 bit shift register fed back it's inverted output
then run through a bunch of gates (see page 2 of the data sheet)
it counts to 10 having one output (Q0-Q9) high for each step.
It's basically the same chip as the 4017B used here.
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
--
⚂⚃ 100% natural
Richard
Guest
Thu Jun 30, 2011 11:50 am
On 30/06/2011 12:30, Jasen Betts wrote:
Quote:
On 2011-06-30, Richard<none_at_ntlworld.com> wrote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
Hi, you've found a data-sheet that's a really good start.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
actually it's a 5 bit shift register fed back it's inverted output
then run through a bunch of gates (see page 2 of the data sheet)
it counts to 10 having one output (Q0-Q9) high for each step.
It's basically the same chip as the 4017B used here.
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
Hi. So it's not a 4 digit counter, it's 10 digit counter, and that is
why we see Q0 -Q9. But there is a 5 shift register in the IC.
Not sure what the code converter is about though.
At present what interests me is a decade counter.
From what I read, for each 7 segment display, you require 4 bits
representing the count, and you are getting Binary Coded Decimal at
Q1-Q4 (because we are using decade counters) and not regular binary
(modulo 16?). So, when building for 7 segment displays you need 4 bits
for every display. Therefore you would need a 16 bit counter (4 x 4 bit)
to run four 7 segment LED displays. I guess so.
Richard
Guest
Thu Jun 30, 2011 11:55 am
On 30/06/2011 12:50, Richard wrote:
Quote:
Hi. So it's not a 4 digit counter, it's 10 digit counter, and that is
why we see Q0 -Q9. But there is a 5 shift register in the IC.
I mean 4 bit and 10 bit.
Richard
Guest
Thu Jun 30, 2011 12:10 pm
On 30/06/2011 11:58, Jon Kirwan wrote:
Quote:
On Thu, 30 Jun 2011 10:29:37 +0100, Richard
none_at_ntlworld.com> wrote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
Examine this java-coded display of one:
http://www.falstad.com/circuit/e-johnsonctr.html
It's a 5-bit ring, but the output of the last bit is inverted
and fed back so it takes two loops through to repeat itself
completely.
Jon
I've not enough knowledge yet to understand these counter IC's.
I've just started learning digital, and all I know about is 4 bit
counters and how you can use those 4 bits (BCD in a decade counter) to
run a 7 segment display (via a BCD decoder).
So, when I think about counters with 7 segment displays, I'm assuming
your counter must be 4 bit, 8 bit, 12 bit etc.
I think this is true except for ring counters.
I just don't know why, with a decade counter, there are 10 bits in the
IC MC14017B-D and not multiples of 4bits.
Josef Moellers
Guest
Thu Jun 30, 2011 12:19 pm
Am 30.6.2011 schrub Richard:
Quote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
They just use different codes:
the 4 bit counter outputs a base-2 code while the 10 bit counter outputs
a 1-out-of-10 code:
base-2 1-out-of-10
0000 0000000001
0001 0000000010
0010 0000000100
0011 0000001000
0100 0000010000
0101 0000100000
0110 0001000000
0111 0010000000
1000 0100000000
1001 1000000000
The 1-out-of-10 counter could just as well be implemented using a base-2
BCD counter (e.g. an SN74LS160A) and a decoder (e.g. an SN74LS145).
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
Josef Moellers
Guest
Thu Jun 30, 2011 12:31 pm
Am 30.6.2011 schrub Richard:
Quote:
On 30/06/2011 11:58, Jon Kirwan wrote:
On Thu, 30 Jun 2011 10:29:37 +0100, Richard
none_at_ntlworld.com> wrote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
Examine this java-coded display of one:
http://www.falstad.com/circuit/e-johnsonctr.html
It's a 5-bit ring, but the output of the last bit is inverted
and fed back so it takes two loops through to repeat itself
completely.
Jon
I've not enough knowledge yet to understand these counter IC's.
I've just started learning digital, and all I know about is 4 bit
counters and how you can use those 4 bits (BCD in a decade counter) to
run a 7 segment display (via a BCD decoder).
It must be a decoder which outputs a special code, as a simple "BCD
decoder" will output a 1-out-of-10 code. What you need is one that
outputs a code geared towards 7-segment displays:
Input Output
0000 1110111
0001 0100100
0010 1011101
0011 1101101
0100 0101110
0101 1101011
0110 1111011
0111 0100101
1000 1111111
1001 1101111
The least significant bit of the output is the top horizontal bar, then
the more significant bits are arranged from top to bottom and from left
to right:
0
+-----+
| |
|1 |2
| 3 |
+-----+
| |
|4 |5
| 6 |
+-----+
Take a look at e.g. the 4511, the 7447 or any other "BCD to 7-segment
decoder/driver".
Quote:
So, when I think about counters with 7 segment displays, I'm assuming
your counter must be 4 bit, 8 bit, 12 bit etc.
It depends upon your display. You might want to count in octal, then a
number of 3-bit counters is sufficient ;-)
Note that the integrated decodes/drivers also have a feature to suppress
leading 0s.
Quote:
I think this is true except for ring counters.
I just don't know why, with a decade counter, there are 10 bits in the
IC MC14017B-D and not multiples of 4bits.
Because the code it outputs is a 1-of-10 code.
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
Richard
Guest
Thu Jun 30, 2011 12:43 pm
On 30/06/2011 13:19, Josef Moellers wrote:
Quote:
Am 30.6.2011 schrub Richard:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
They just use different codes:
the 4 bit counter outputs a base-2 code while the 10 bit counter outputs
a 1-out-of-10 code:
base-2 1-out-of-10
0000 0000000001
0001 0000000010
0010 0000000100
0011 0000001000
0100 0000010000
0101 0000100000
0110 0001000000
0111 0010000000
1000 0100000000
1001 1000000000
The 1-out-of-10 counter could just as well be implemented using a base-2
BCD counter (e.g. an SN74LS160A) and a decoder (e.g. an SN74LS145).
Josef
Hi. Yes, the 4 bit counters that I am reading about are all binary
counters. Even the decade (BCD) counter is, except that BCD in the whole
sequence of bits are not binary.
And in this scheme I see how each display LED requires a Q1-Q4 output
from a 4 bit counter.
So to display a count of 7953 we need four, 4 bit counters:
Q1-Q4 Q1-Q4 Q1-Q4 Q1-Q4
BCD sequence:......... 0111 1001 0101 0011
Decimal displayed:.......... 7 9 5 3
Output of 4 bit counter is base-2 code.
Not sure yet how you would get to display 7953 using the 10 bit counter.
Whether in fact you would or could use 7 segment LED displays.
John Fields
Guest
Thu Jun 30, 2011 1:02 pm
On 30 Jun 2011 11:30:26 GMT, Jasen Betts <jasen_at_xnet.co.nz> wrote:
Quote:
On 2011-06-30, Richard <none_at_ntlworld.com> wrote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
Hi, you've found a data-sheet that's a really good start.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
actually it's a 5 bit shift register fed back it's inverted output
then run through a bunch of gates (see page 2 of the data sheet)
---
It's actually a 5 stage Johnson counter; a shift register is quite a
different animal.
---
Quote:
it counts to 10 having one output (Q0-Q9) high for each step.
It's basically the same chip as the 4017B used here.
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.
--
JF
John Fields
Guest
Thu Jun 30, 2011 1:08 pm
On Thu, 30 Jun 2011 10:29:37 +0100, Richard <none_at_ntlworld.com> wrote:
Quote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
In a 4 bit counter the output is at Q1, Q2, Q3 and Q4. We can feed these
4 bits (from a decade counter usually) into a decoder to drive a 7
segment display.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
---
It's actually more like a tricky 4 bit counter which only uses 10 of
the possible 16 output steps and presents them on the outputs one at a
time.
--
JF
Richard
Guest
Thu Jun 30, 2011 1:14 pm
So to display a count of 7953 we need four, 4 bit counters:
........................ Q1-Q4 Q1-Q4 Q1-Q4 Q1-Q4
BCD sequence:.......... 0111 1001 0101 0011
Decimal displayed:..... 7 9 5 3
(on 7 segment LED)
Output of 4 bit counter is base-2 code.
---
Basically, how would you complete the above arrangement for this 10 bit
counter:
........................ Q0 Q1 Q2 Q3 Q$ Q5 Q6 Q7 Q8 Q9
??? sequence:..........
Decimal displayed:..... 7 9 5 3
(on 7 segment LED)
Richard
Guest
Thu Jun 30, 2011 1:23 pm
So to display a count of 7953 we need four, 4 bit counters:
........................ Q1-Q4 Q1-Q4 Q1-Q4 Q1-Q4
BCD sequence:.......... 0111 1001 0101 0011
BCD decoder (to drive LED driver)
Decimal displayed:..... 7 9 5 3
(on four 7 segment LEDs)
Output of each 4 bit counter is base-2 code.
---
Basically, how would you make out a similar arrangement to the above for
the 10 bit counter? What would it take to display 7953 on four seven
segment display LEDs? How many counters?
........................ Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9
??? sequence:..........
??? decoder:..........
Decimal displayed:..... 7 9 5 3
(on four 7 segment LEDs)
Richard
Guest
Thu Jun 30, 2011 1:40 pm
On 30/06/2011 14:23, Richard wrote:
Quote:
So to display a count of 7953 we need four, 4 bit counters:
....................... Q1-Q4 Q1-Q4 Q1-Q4 Q1-Q4
BCD sequence:.......... 0111 1001 0101 0011
BCD decoder (to drive LED driver)
Decimal displayed:..... 7 9 5 3
(on four 7 segment LEDs)
Output of each 4 bit counter is base-2 code.
---
Basically, how would you make out a similar arrangement to the above for
the 10 bit counter? What would it take to display 7953 on four seven
segment display LEDs? How many counters?
....................... Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9
??? sequence:..........
??? decoder:..........
Decimal displayed:..... 7 9 5 3
(on four 7 segment LEDs)
Are we saying for 10 bit counter when the count reaches 7953 we have:
........................ Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9
1 in 10 sequence:...... X X X X
X = HIGH
1 in 10 decoder: (To drive LED driver)
Decimal displayed:..... 7 9 5 3
(on four 7 segment LEDs)
John Fields
Guest
Thu Jun 30, 2011 1:50 pm
On Thu, 30 Jun 2011 12:50:51 +0100, Richard <none_at_ntlworld.com> wrote:
Quote:
On 30/06/2011 12:30, Jasen Betts wrote:
On 2011-06-30, Richard<none_at_ntlworld.com> wrote:
MC14017B
http://www.onsemi.com/pub_link/Collateral/MC14017B-D.PDF
I've just begun to look at digital electronics, and of course I have
come across the 4 bit counter.
Hi, you've found a data-sheet that's a really good start.
MC14017B is a 5 stage counter with built in code converter and shows
outputs Q0 - Q9.
Is this actually like a 5 bit counter, or what? Thanks.
actually it's a 5 bit shift register fed back it's inverted output
then run through a bunch of gates (see page 2 of the data sheet)
it counts to 10 having one output (Q0-Q9) high for each step.
It's basically the same chip as the 4017B used here.
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
Hi. So it's not a 4 digit counter, it's 10 digit counter, and that is
why we see Q0 -Q9. But there is a 5 shift register in the IC.
Not sure what the code converter is about though.
At present what interests me is a decade counter.
From what I read, for each 7 segment display, you require 4 bits
representing the count, and you are getting Binary Coded Decimal at
Q1-Q4 (because we are using decade counters) and not regular binary
(modulo 16?). So, when building for 7 segment displays you need 4 bits
for every display. Therefore you would need a 16 bit counter (4 x 4 bit)
to run four 7 segment LED displays. I guess so.
---
Almost.
Here's the difference between the counting patterns of decade and
binary counters outputs:
CLOCK DECADE BINARY
0UT OUT
0 0000 0000
1 0001 0001
2 0010 0010
3 0011 0011
4 0100 0100
5 0101 0101
6 0110 0110
7 0111 0111
8 1000 1000
9 1001 1001
10 0000 <- 1010
11 0001 1011
12 0010 1100
13 0011 1101
14 0100 1110
15 0101 1111
16 0110 0000 <-
Notice that the decade counter overflows at the 10th clock, while the
binary counter overflows at the 16th.
That means that if a binary counter is used to drive a BCD to
7-segment decoder, the decoder won't display anything between 1001 and
0000.
So, the most rudimentary way to drive 4, 7 segment displays would be
to use 4, 4 bit BCD counters, 4 BCD to 7 segment displays, and 4,
7-segment displays.
--
JF
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