0
\$\begingroup\$

For a binary up/down counter with synchronous clear and preset , my question is what is the exact function of the preset here ? I have done many searches but every source assumes that the reader knows what is the preset function is and just mentions that the counter does have a preset input.

\$\endgroup\$

2 Answers 2

1
\$\begingroup\$

what is the exact function of the preset here ?

The preset input is usually several parallel inputs that can be loaded into the counter via an enable input such as in the MC14516: -

enter image description here

Once a number is preset, you can count up or down from that value.

Another device (uses "Preset Load"): -

enter image description here

\$\endgroup\$
0
\$\begingroup\$

Since you mentioned "synchronous clear and preset", they are no different from any other counter control or counter data signals. They all traverse through combinational cloud, and finally converge at the D pin of several flip-flops. From the perspective of circuit, synchronous clear or preset are just DATA. We human beings call them clear or preset signal just because they do the clear or preset job functionally. So this is not an essential issue.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.