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.

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.

Pre-presentation Self Assessment Activity Configure a 74161 so that it can start counting at any value from 0 to F. 1. 2. Configure the 74161 so that it will count in base 3.

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

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

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.

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.

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

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.

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.

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.

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

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

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

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

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

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.

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.

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.

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.

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 74161 is known as a “look ahead” synchronous counter. This output goes active when count reaches last value.

Post Presentation Self Assessment Activity 1. Configure a 74161 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.

Post Presentation Self Assessment Activity 2. Configure the 74161 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.

End of Presentation A G Inc.