Calculator Icon

[David]

Hi
I've just started using the Hardware Simulator. I am looking at the Xor file. I can load the file into the simulator. I have watched the tutorial video very carefully. When he chages the inputy pins the calculator icon lights up before that it is greyed out. When I do the same thing on my pc I cannot get the calculator to change from being greyed out to a coloured icon. Please help

[WBahn]

I don't have the tools installed on this machine, so I'm not in a position to play with things right now.

Could you post a link to the video you are talking about, and perhaps a time hack? I'll take a look.

Most of the problems that people run into with the Xor example is that the book talks about it before the student implements the parts needed to build it. So they implement it using those parts and the simulator then loads the empty parts (because the template files are in the same directory) and it can't run.

If that's the problem, then you can move (or rename) the parts used in the Xor to another directory (for now) or you could copy your Xor to another directory and run it from there.

[a1ph4byte]

I have the same issue. Use of the Eval button is hit or miss, although I find if I use the Run button, I get the results I need. Is there a difference between Run and Eval buttons?

[WBahn]

Are your other parts (Not, And, and Or) implemented and do they work?
 

[a1ph4byte]

WBahn,

You are correct, this detail gets me every single time. I selected the Xor chip from the chapter one folder in which none of the other chips are implemented.

When I put the Xor.hdl into its own folder by itself. The clock icon enables. When the inputs are changed.

[WBahn]

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.

[a1ph4byte]

Okay.. back again... Having same issue with the eval button being greyed out, but this time I have ensured that all of the chips are built in.

Any ideas?

[a1ph4byte]

Answer:

Full chip must be implemented. If something like out=out is not specified, then eval wont be enabled. At least that was my issue.