Re: Calculator Icon

Posted by WBahn on Jan 08, 2023; 12:26am
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/Calculator-Icon-tp4037020p4037034.html

This is a common and recurring source of frustration for people. While the text does talk about how to use the built-in parts, it isn't terribly clear and, frankly, most people don't pay much attention to it.

It's understandable that when they see the Xor chip implemented in the book that they assume that they can just implement it the same way and expect it to work. I don't think the book even makes mention of the need to implement the other chips first or to move it to another folder (maybe the 2nd Ed does).

I think a better chip to use as a demo would be to implement a Nor gate. Since that happens to not be used in the design of the N2T hardware, they could walk through the logic of getting it two work with four Nand gates and then show the code to implement it. Doing so would also give a big hint as to how to get started with implementing the Not gate.