I need help. Our requirements is to make our 7 segment display count up and down, we have a circuit but it only counts up, how can we modify it to count down? All answers will be highly appreciated.
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Is this homework? Even if it isn't, most members draw the line at doing more work then the requester.All answers will be highly appreciated.
??Invert output of U3.
There are restrictions with the components. We need to use those componentsWelcome to AAC!
Is this homework? Even if it isn't, most members draw the line at doing more work then the requester.
Are there any restrictions on the components you can use to implement this circuit?
Thankyou!
I'd say it would be difficult with an up counter with preset capability, and impossible with 7490.There are restrictions with the components. We need to use those components
Most of my classmates did that but my professor isn't satisfied. He said we should modify our circuit and not change components.The easiest is to use an up/down counter such as a 74190.
Is it really impossible? He said we can modify our circuit, and use inverter or add more logic gates.I'd say it would be difficult with an up counter with preset capability, and impossible with 7490.
Since it isn't very educational to assign problems that can't be solved for school work, there must be something you've misunderstood.
We'll try that. Thankyou!Hi
Use inverters to invert the output of U2. The counter will still count up but the display will count down.
eT
Think about this before you run off half cocked. You have a BCD up counter.We'll try that. Thankyou!
Thankyou!Here's a table of the up and down binary numbers and decimal equivalents.
I see no obvious way, other than a lookup table in ROM, to change the up count to an equivalent down count.
View attachment 145122
Yes...if U2 were a binary counter, you could simply invert all outputs. But its a BCD counter.Think about this before you run off half cocked. You have a BCD up counter.
What do you get when you invert 0000? Is that a valid BCD digit? What do you get when you invert 0001?
by Duane Benson
by Jake Hertz
by Jake Hertz