For example, if we have a OR gate, one input depends on us and the other input is like the feedback from the output, how can we generate the truth table? Thank you!
If it starts from initial state and say Controlled input is 0= then output will be latched to 0. Because the controlled input is 0 and the fed back value is also 0. There is no way the fed back value could be set to 1 without changing the controlled input.
Once you set control input to 1- no matter what the feedback it- it will latch to 1 for ever.
Hi dhaval4987, thank you for your explanation! I am just doing some execises and found this problem. So it means we can write down the truth table like this:
Input Output(also the other input)'
0 0
1 1
Is it correct? Becasue I am thinking about that if the input is 0, the output can be 1 because 0(OR)1=1, should I write the truth table as
Input Output(also the other input)'
0 0
0 1
1 1
? Please advise!
If it starts from initial state and say Controlled input is 0= then output will be latched to 0. Because the controlled input is 0 and the fed back value is also 0. There is no way the fed back value could be set to 1 without changing the controlled input.
Once you set control input to 1- no matter what the feedback it- it will latch to 1 for ever.
Controlled Fed back Out
0 0 0
0 1 1 : This case is invalid in the beginning when Controlled lines do not change. Coz how will output change if Controlled input is 0!? Do you get what I mean?
Once the controlled input is set to 1 then output will be 1 for rest of the cases, even if you switch the controlled line to 0. (The case above becomes realistic).
Hi Andre,thank you for your reply! But I am still not sure from your statement, whenY=1, US=1, why OUT=X? This is an OR gate and Y equals to OUT, could you give me some more guidance?
Yes I got you! So I should make a statement to say that once Controlled is 1, the output will be 1 and even if Controlled changed back to 0, the output is still 1, am I right?
Controlled Fed back Out
0 0 0
0 1 1 : This case is invalid in the beginning when Controlled lines do not change. Coz how will output change if Controlled input is 0!? Do you get what I mean?
Once the controlled input is set to 1 then output will be 1 for rest of the cases, even if you switch the controlled line to 0. (The case above becomes realistic).
Sorry Andre I am still a little bit confused. Could you tell me more about this?
Y US OUT
1 1 x
1 0 1
From here you said even if there is a wire (or connection) between the output and Y, it is still possibel that Y=1. US=1 and OUT=0 because it is latched?
---------- Post added at 01:35 ---------- Previous post was at 01:31 ----------
Yes I know this. So you are saying that now the truth table should be written according to time but not combination? If it is true, could you tell me how?