These types can store data, meaning that their behaviour is similar to variables in other programming languages such as C.īoth of these families contain a number of different types which we can use in our code. We primarily use the variable types to model registers or flip flops in our design. They are unable to store values on their own and must be driven with data. We use the net types to model point to point connections in our digital circuits. We use these two different groups to model different elements of our digital circuits. In verilog, we can split the binary data types into groups - net types and variables types. Let's look at all of the basic SystemVerilog types in more detail. The code snippet below shows this general syntax. Regardless of the exact type of data we are using, we always use the same syntax to declare a variable in SystemVerilog. We use these types to model either whole or decimal numbers in our SystemVerilog code. The second family consists of types which we use to model numerical data. We mainly use these types to model simple logic components, connections and busses. One of these families consists of types which are used to model basic binary data in our code. Basic SystemVerilog Data Typesīroadly speaking, we can split the SystemVerilog types into two distinct families. SystemVerilog 2 state equivalent to integerĨ bit signed type to model whole numbers in SystemVerilogġ6 bit signed type to model whole numbers in SystemVerilogĦ4 bit signed type to model whole numbers in SystemVerilogĦ4 bit unsigned number which represents simulation timeĮach of these types is described in more depth in the following sections. SystemVerilog replacement for reg and wireģ2 bit signed type to model whole numbers in Verilog It also shows which types use the old verilog 4 state encoding and which use 2 state encoding. The table below shows all of the different types which we can use in SystemVerilog.

Therefore, we should only use these data types in SystemVerilog testbenches.Īs they have half as many states, the SystemVerilog 2 state types use half as much memory as the 4 state verilog types.Īs a result of this, the 2 state types have faster execution times than their equivalent 4 state type. When we use the 2 state data types in SystemVerilog, we can only assign a logical 1 or 0 to the individual bits. These types are intended to be simpler, more efficient versions of the 4 state types from verilog. However, a number of 2 state data types were introduced as a part of the SystemVerilog extension. We require the high impedance and unknown states to more accurately represent the underlying hardware we are describing in verilog. These different states are shown in the table below. In verilog, we can assign four different states to the individual bits in our data. The code snippet below shows the general syntax we use to represent digital data in SystemVerilog. Therefore, we can create data busses which contain as many bits as we choose. This is because we are describing hardware circuits when we use SystemVerilog. Unlike in other programming languages, we also need to define the number of bits we have in our data representation. We can express this data as either a binary, hexadecimal or octal value. When we write SystemVerilog, we often need to represent digital data in our code. In this post, we look at both the older verilog data types and the newer SystemVerilog types. In addition to this, a number of new types were introduced as a part of the SystemVerilog standard. When we assign data to a signal in SystemVerilog, the data is implicitly converted to the correct type in most cases.Īs a result, there is often no need necessary to explicitly perform type conversions in verilog.Īs SystemVerilog is an extension of verilog, we can use all of the existing verilog data types in our code. We can also use types which interpret our data as if it were a numeric value. We can use types which interpret data purely as a logical value, for example.

The type which we specify is used to define the characteristics of our data. This includes a discussion of data representation, 2 state vs 4 state types, binary data types and numerical data types.Īlthough SystemVerilog is considered to be a loosely typed language, we must still declare a data type for every port or signal in our SystemVerilog design. In this post, we talk about the most commonly used data types in SystemVerilog.

System verilog decimal to binary