1. Counting with the Count.
This presentation is partially animated. Only use the control panel at the bottom of screen to review what you have seen. When using your mouse, make sure you click only when it is within the light blue frame that surrounds each slide. A G
Inc.

2. Pre-presentation Self Assessment Activity
Your comfort level with your response to the following two question assessment tool should indicate if the presentation that follows will increase you knowledge base on the topic outlined by the questions in this tool.

3. Pre-presentation Self Assessment Activity
Configure a so that it can start counting at any value from 0 to F. 1. 2.
Configure the so that it will count in base 3.

4. Famous Counters 1 Q A B C D
Clear
74161 Ck
5 volts

5. Push this button to clear the counter outputs
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
The next clock pulse that arrive at the Ck pin will change the LED pattern to indicate that the first event has occurred. 1

6. Famous Counters Q A B C D
Clear
74161 Ck
5 volts
The next clock pulse that arrive at the Ck pin will change the LED pattern to indicate that the first event has occurred. 1
After the next clock pulse the LED pattern will indicate that the second event has occurred.

7. Famous Counters Q A B C D
Clear
74161 Ck
5 volts
The next clock pulse that arrive at the Ck pin will change the LED pattern to indicate that the first event has occurred. 1 1
After the next clock pulse the LED pattern will indicate that the third event has occurred.

8. Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Now it is time to examine additional features of this and other counters. 1 1

9. Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Now it is time to examine additional features of this and other counters. 1 1 B A C D
Note;
(a) A, B, C, D are input pins.
(b) Any 4 bit digital signal can
be placed on these inputs.
(c) Following a specific sequence
of events, the pattern on these
4 input pins is transferred to the
set of Q output pins.
(d) In this example, the digital signal encoded as an 816 has been placed on
these input pins.

10. Clear Load 1 A B C 1 D Ck 74161 5 volts Q A B C D 5 V Note;
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
5 V
Load 1 1 B A C D
Note;
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.

11. Clear Load 1 A B C 1 1 D Ck 74161 5 volts Q A B C D 5 V
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive
Load push button is active
Load push button is passive again
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the 916.
The 816 was transferred to the Q outputs after a CK pulse occurs.

12. Clear Load 1 A B C 1 1 D Ck 74161 5 volts Q A B C D 5 V
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the 916.
916

13. Clear Load 1 A 1 B C 1 D Ck 74161 5 volts Q A B C D 5 V
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the A16.
A16
916

14. Clear Load 1 A 1 B C 1 D Ck 74161 5 volts Q A B C D 5 V
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the B16.
B16
A16

15. Clear Load 1 A B C 1 1 D Ck 74161 5 volts Q A B C D 5 V
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the C16.
C16
B16

16. Clear Load 1 A B C 1 1 D Ck 74161 5 volts Q A B C D 5 V
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the D16.
D16
C16

17. Clear Ck Load 1 1 1 B A C D Carry
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
E16
D16
5 V
(e) If the load pin is active
when a clock pulse is
detected, the pattern for
the 816 is transferred to the
set of Q outputs.
Load 1 1 1 B A C D
(f) No data transfer until after a
clock pulse occurs
Carry
(g) The next clock pulse (if Load stays
passive) will change the output to
indicate the E16.

18. Clear Ck Load 1 1 1 B A C D Carry
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
E16
D16
5 V
(h) The Carry output goes
active when the counter
reaches its final count value.
Load 1 1 1 B A C D
Carry
This output goes active when count reaches last value.

19. Clear Ck Load 1 1 1 B A C D 1 Carry
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
F16
E16
5 V
(h) The Carry output goes
active when the counter
reaches its final count value.
Load 1 1 1 B A C D 1
Carry
(i) The next clock pulse (if Load stays
passive) will change the output to
indicate the 016.
This output goes active when count reaches last value.

20. Clear Ck Load 1 1 B A C D 1 Carry
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
016
F16
5 V
(h) The Carry output goes
active when the counter
reaches its final count value.
Load 1 1 B A C D 1
Carry
(i) The next clock pulse (if Load stays
passive) will change the output to
indicate the 016.
This output goes active when count reaches last value.

21. Clear Ck Load 1 1 B A C D 1 Carry
Famous Counters Q A B C D
Clear
74161 Ck
5 volts
Load push button is passive again
016
F16
5 V
(j) A Carry pin that goes active
before the end of the count is
know as a “look ahead” Carry.
Some counters do not have this
feature.
Load 1 1 B A C D
(k) Some counters load the output
pins from the input pins immediately
after Load becomes active. Those
types of counters are call
asynchronous counters. 1
Carry
(l) The is known as a “look ahead”
synchronous counter.
This output goes active when count reaches last value.

22. Post Presentation Self Assessment Activity1.
Configure a so that it can start counting at any value from 0 to F. Q A B C D
Clear
74161 Ck
Load
Carry 5V
Note:
In this configuration the counter starts with pattern 0,0,0,0 on its outputs and sequentially uses the other 15 binary patterns with the carry pin going active when the binary pattern 1,1,1,1 is on its outputs.

23. Post Presentation Self Assessment Activity2.
Configure the so that it will count in base 3. Q A B C D
Clear
74161 Ck
Load
Carry 5V 5V
Note:
In this configuration the counter starts with pattern 1,1,0,1 on QD,QC,QB,QA, respectfully (D16). its sequentially uses the remaining 2 binary patterns with the carry pin going active when the binary pattern 1,1,1,1 is on its outputs.

24. End of Presentation A G
Inc.