Re: I do not understand the math notation in this chapter.

Posted by AverageOyster on
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/I-do-not-understand-the-math-notation-in-this-chapter-tp4032141p4032160.html

Mark, I was playing around with the D flip-flop simulation on that website you posted and saw something which confused me. The D flip-flop on the website seems to behave differently from the DFF built-in chip included with the Nand2Tetris software package. The DFF on the website appears to output whatever value is seen at D during the falling clock edge, whereas the DFF built-in chip appears to "take in" whatever input value is seen at the rising clock edge and then output that "taken in" value at the falling clock edge regardless of the value of the input at the falling clock edge. From what I've read in a digital logic textbook I have, it seems like the DFF on the website more accurately reflects the true behavior of real DFFs.

Are you able to comment on this discrepancy at all? Why doesn't the odd behavior of the built-in DFF cause problems later on? If the way I described the discrepancy doesn't make sense then I can provide a concrete example of what I'm talking about.