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Walk over to the VHDL did type introduction and this lecture I'm going to introduce the different datatypes

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associated with the HGL.

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First we have data classes which are used to describe the data types based on data class will limit

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you or allow you to do certain things with that specific data type.

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So the day classes are we have constants signals variables and files.

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So with constants at a high level they are a value that can never change.

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A signal is a value that is constantly changing inside of your design and a variable is something we

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use to help you construct your designs and files our views and test benches to help you simulate and

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verify your design is working properly.

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The data types we have here are a number of data types we'll be using in the HDL.

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We have a standard logic standard logic vector and unsigned signed integer and a boolean data type.

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Each data type is associate with that data class except for files.

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Those we're using for simulations only.

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So for example we had the constants and the signals.

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So I could have a constant That's a standard logic and I could have a signal that the standard logic.

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And based upon the different types if it's a constant state in logic it can never change or it's a signal

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standard logic.

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Now that value can change.

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So based upon the data types and the data class that you're using it will dictate what you can and can

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do with that specific signal or constant or whatever you are you're working with the kind of help you

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create your designs.

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So why do we use data types inside of an FPGA.

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Everything is a one or zero.

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Just like a computer.

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Well the reason wreathing data types is this allows us to group these ones and zeros in a way that's

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easy for us to understand.

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If we see a group of one and zeros inherently to the human eye it just doesn't really make a lot of

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sense.

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It's hard to understand what's going on.

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But if we can see a number like say ninety nine 100 101 102 to us it's easy to tell it OK.

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That number is counting.

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And so that's the reason we use data types.

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It helps us group these ones and zeroes so we can make our design happen in a way that's understandable

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to us humans that the computer or your FPGA can then interpret and execute these commands enough talking

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about the data types.

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Let's actually learn the specifics.