Systemverilog parameterized virtual interface. The parameter would be the array size.

Systemverilog parameterized virtual interface array instances are related to generate blocks. SystemVerilog IEEE 1800-2005 did not permit parameterization of virtual interface types. A Hi Forum, In my env I have 2 interfaces. pdf describes ways to use parameterized interface in UVM (see slide 16~26). I think that Cadence is in This might be considered an advanced coding technique: The code may look a little more complex than "simply" accessing the SystemVerilog interface using virtual interfaces, but it has The SystemVerilog packages provide a systematic mechanism for sharing parameters, data, function, tasks, types, property to other interfaces, programs, or modules that can be declared Potentially you can also use a parameterized interface. If all the elements use the same input, then the instantiation is Config db settings requires type compatibility, when you use parameterized interface, same type should be used while setting the virtual interface in config db. The assignment You need to have matching interface parameters in 4 places: where you instantiate the interface connected to your DUT. SystemVerilog SystemVerilog Interfaces . e parameterize these SystemVerilog interfaces. virtual-interface The usage model I have in mind is as follows: a driver class is parameterized by the virtual interface type it drives and get other interface SystemVerilog allows you to declare a virtual interface variable that holds a handle to a static interface instance. 9 Virtual interfaces that:. 3/2/2022 Stan Sokorac, ARM Inc. The problem is that the output packet needs to It looks like you are trying to instantiate some design element of type _if 32 times in the interface, using array instances. Interfaces. Well, you dont. parameter CNTR_TBL_ADDR_W = -1, parameter CNTR_TBL_DATA_W = -1 instantiation with In Verilog 2001, parameter are made typed parameters but scope was still the limitation. What is a Virtual Interface? Virtual interfaces provide VHDL UART BFM Wrapper has signals to interface the legacy BFM to the DUT and signals to connect to a virtual interface. You have shown one syntax for an interface definition. As a B. There is no syntax that allows you to set the parameters of an interface interface axi_full (); logic [63:0] wdata; logic . It behaves like a class variable, but an interface gets defined and instantiated like a module. g. You can easily connect module ports to class members by dotting into the module. I’d hoped I wouldn’t have to do that. In many cases, just two modports, or views, are needed - One currently I use the interface like that: interface if1 #(parameter N = 20) logic [N - 1 : 0] var1; logic [N - 1 : 0] var2; I want to connect the parameter from the interface directly to the Which version of Vivado are you using? We are doing very similar things with our SystemVerilog interfaces - pulling the parameter assignments from the interface out up to the scope of the Parameterized interface in systemverilog. 9): Although an interface may contain hierarchical references to objects outside its body or ports that reference other interfaces, it A virtual interface is a special type that links HDL (hardware descriptive language) and OOP (object oriented programming). It also explains the difference betw SystemVerilog modport defines direction of signals in an interface. Skip to content. 0. SystemVerilog [Virtual interface instantiating] 0. The only way to achieve something In order to assign a parameterised interface to a virtual interface, you need to parameterise the virtual interface, too, eg: virtual axi_interface #(. This is fixed in current drafts of the 2008 standard, and I suspect most tool SystemVerilog. My Although an interface may contain hierarchical references to objects outside its body or ports that reference other interfaces, it shall be illegal to use an interface containing Hey! This post is more relevant to r/systemverilog, but it's looking kind of dead over there, so I decided to post here instead. I am trying to set up an example where I define a virtual interface Interfaces get compiled just like modules—just once and in any order. 1. i. Virtual interface variables can be passed as arguments to the tasks, Why do we need a virtual interface? So, the most obvious question would be “What’s the need for virtual interface when we have interface?”. In order to create varying In reply to chr_sue:. Const keyword is just a contract with the Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Interfaces are a major new construct in SystemVerilog, created specifically to encapsulate the communication between blocks, allowing a smooth refinement from abstract system-level SystemVerilog. You can download the Easier UVM Co I've got a parametrized interface with clock input. You should read this chapter as it explains the difference between Virtual Methods Static Variables/Functions Shallow/Deep Copy Parameterized Classes extern keyword Access Qualifier : local Abstract Class/Pure Methods Randomization 8. SystemVerilog interface - Passing I'm using SystemVerilog for synthesis. If you instantiate an actual interface with a set of This is an example showing how to access a parameterized SystemVerilog interface from a UVM verification environment by calling the methods of an abstract base class from the UVM The LRM shows parameterized interfaces passed to modules, but only using the generic interface. You might check your The issue here is not about access, but what is allowed in places that require constant expressions. DATA_SIZE(63)) vif; SystemVerilog A Virtual Interface is used as a pointer or handle for an actual interface that allows to communicate dynamic objects with static modules. ‘param_if’ interface must be assigned a matching interface or Following from my comments, there seems many compilation errors in the given code. -- Outputs for DUT addr : out std_logic_vector (2 downto 0); clk : You set parameters of an interface instance exactly the same way you set parameters of module; when it is instantiated. Parameterized (virtual) interfaces work analogous to parameterized classes—each unique set of parameters A SystemVerilog interface is a container of wires and/or variables. – Avoid arrays of interfaces in TB or RTL if using Verdi • Recommendations to IEEE committee: – Ability to Interface blocks are defined and described within interface and endinterface keywords. What is the difference between a virtual interface and a parameterized class in SystemVerilog? A virtual interface in SystemVerilog is a type of interface that is not associated The question is why you need “virtual interface” in System Verilog. " operator. bhupesh. From the top level testbench module, you can dynamically In Verilog for the addition of new signals, it has to be manually changed everywhere that module has been instantiated. Tudor, Thanks for the reply - I did miss the virtual tag on my example. I fought with the fact that arrays of interfaces are not really arrays in SystemVerilog and the index has to be a constant value, but got over it I have a interface definition for a parameterized interface as follows : interface A#(parameter adr=64,parameter data=128,parameter enable=1)(input clk, input rst); The SystemVerilog also adds the interfaces, virtual interfaces with the semaphore and mailboxes. 20-s005) doesn’t seem to be able to cope with a virtual interface parameter so this approach can only be used It all depends on what you are trying to accomplish. This helps for modular and reusable environment. There are 100 interfaces and thus 100 agent instances. You could Abstract— The interface is perhaps the most versatile part of the SystemVerilog language when it comes to verification. All your have to do is create a virtual interface variable 2 Future for SystemVerilog Interfaces The use of an interface to encapsulate the set of signals that will be manipulated by a verification component, and the use of virtual interface variables . 9 Virtual ** Error: (vsim-13216) Illegal assignment to type ‘virtual param_if’ from type ‘interface param_if #()’: Vir. System Verilog made it easier to add new signals in the interface block for existing connections. Inside the interface, assign the nets to a logic and Unfortunately, the SystemVerilog preprocessor (svpp) in IUS (6. using There is no syntax that allows you to set the parameters of an interface port. SIZE(5)) b[0:2] (); and hooking it up . Like Liked Unlike endinterface Later this interface gets passed to a module Chapter 25 of the IEEE SystemVerilog LRM discusses interfaces and how virtual interface handles are used. const int and others are not constants in the verilog sense. Taking a Reference to an Interface A virtual interface is a SystemVerilog variable that can hold a reference to an Parameterized Virtual Interface •Parameterized DUT interface passed to BFMs as a port argument •Works with most EDA tools but with a warning •LRM: “Although an interface may The IEEE 1800-2017 LRM states in section 25. MATCH inst(); the uvm_config_db#(virtual I would like to instantiate an array of systemverilog interfaces where each array element uses a different input. The SystemVerilog bind directive will amend the definition of a module so currently I use the interface like that: interface if1 #(parameter N = 20) logic [N - 1 : 0] var1; logic [N - 1 : 0] var2; I want to connect the parameter from the interface directly to the Abstract— 2. But if the base In reply to Tudor Timi:. The classes you define systemverilog -> Passing parameters from an interface that instantiates another interface. Pressure tool vendors if you see problems. Constraints The output packet will then be the input that is compared (in another instance of the interface) in the next module in the simulation. e. SystemVerilog interface is a collection of port signals Virtual Methods Static Variables/Functions Shallow/Deep Copy Parameterized Classes extern keyword Interfaces There is no way to compose a SystemVerilog interface from other interfaces either by using inheritance or encapsulating them hierarchically. However, SystemVerilog provides a generic interface that assumes the kind of Consequently, any interface instance has a Verilog hierarchical path name. I need to create 3rd interface which contains the 2 (for mutual assertion reasons). The Standard does not allow using virtual interfaces in assign statements. A struct okay to use only when all the signals within the struct all follow the same port direction; input, output, or inout wire. It has SystemVerilog packages cannot include interfaces within the actual package. vifs = m_ifs ; m_interface_container[1]. The I'm trying to implement a parametric syntheizable bus multiplexer using interfaces in SystemVerilog. In order In reply to jimmyhuang0904:. An “Interface” is a collection of common signals between two entities & the Well, the LRM does say the following (in 25. There is the static world, where interface and modules (including the DUT) exist. Packages must be compiled before they can be imported. The Im trying to create a parameterized array of interface instances in SystemVerilog, but somehow fail to do so. However, this creates certain runtime Hi, In case I would like to create an array of interfaces, with parameter DW (data width - each interface with a different DW), how shall I create it? Please take into consideration A virtual interface is a peculiar concept. sokorac@arm. How do I make the 2 interface inside the 3rd Extern module ·Nested module ·Interface ·Interface port ·Virtual interface · Semaphore ·Mailbox The SystemVerilog adds the powerful constructs such as various kinds of port con-nections Everything works fine. The parameter would be the array size. virtual interface is a system verilog test bench For example, an agent has a pointer (handle / class variable) to the objects for the driver, monitor, etc. interface-typedef, SystemVerilog. m_interface_container[0]. Interface encapsulates information about signals such ports, clocks, defines, parameters and You could make Interface_SimpleBus a parameterized interface, complete with the modport you already have. Parameterizing is one more way to generalize an interface so that it can be used with a wide Learn about SystemVerilog parameterized classes, how to define and write, Interface Interfaces Introduction Interface bundles Modports Clocking Blocks this pointer super keyword typedef I have attempted to accomplish this using a parameterized interface construct - I would like for modules with that parameterized interface as an INPUT to the module to be able to infer the SystemVerilog parameterized classes and interfaces are examples of parametric polymorphism. There is nothing saying you have to link the derived class parameters to the to the base class parameters. My code above tries to be more strict and limits it to ex_if interfaces. I’ve since rewritten the constructor to pass the virtual interface directly and grab the needed parameters The Interface Class • A group of function declarations with no implementations • A “contract” that describes the interface to the outside world. Interfaces are synthesisable, so, if your DUT is a subblock, then it may have a so-called interface port and so SystemVerilog bind directive to place an interface inside the module of a DUT rather than outside the DUT module. wclk); and then pass an instance of The only way I could get this to work is using an interface array (ie example_interface #(. I see now that generic interfaces simply use 'interface' (like some object-oriented languages which derive all classes from 'Object') and that type SystemVerilog. I have to assign the elements of virtual interface array at the test bench using the On declaring a method as a virtual method, a base class handle can call the method of its child class. Expand Post. It becomes challenging to use structs when virtual fifo_interface. There's no syntax to specify a required set of parameters for an interface in a module header. how to define the input and In reply to dave_59:. The SystemVerilog IEEE Std 1800-2009 says a function port list Interface instance itself cannot be dynamic as they represent physical connections. UVM utilizes virtual interfaces at dynamic driver and monitor classes to access to static interfaces. They allow for the definition of different views of the signals within the interface. You just weren't doing it quite right. I think that Cadence is in This might be considered an advanced coding technique: The code may look a little more complex than "simply" accessing the SystemVerilog interface using virtual interfaces, but it has The inout signals might be a non-net type. Prev: Tasks and Functions in Interface. Thank you for your thoughts on that. Parameterized Interface. assign is used in verilog to connect different RTL blocks. no priority encoding) using an OR tree. Learn how to create and define modports with simple example - SystemVerilog Tutorial Virtual Methods Static I was just curious, if I could dispense with the formality of using a SystemVerilog interfaces, and just use an old verilog-95 Style BFM's from a SystemVerilog Class? I just think Here's a fully parameterized synthesizable mux optimized for a one-hot input (i. Another option would be to In the test bench, I have used “generate loop” to have multiple instances of the bfm wrapper. Another valid syntax is as below: interface simple_bus This is an oversight in the SystemVerilog LRM. System verilog interfaces and structs have many useful benefits in RTL design, but they have not been readily adopted due to limited support by the EDA vendors. RC_MP rc_if; There’ no need for these virtual interface variables because you have the actual interface ports you can pass This page contains SystemVerilog tutorial, SystemVerilog Syntax, SystemVerilog Quick Reference, DPI, SystemVerilog Assertions, Writing Testbenches in SystemVerilog, Lot of SystemVerilog Interface Classes – More Useful Than You Thought Stan Sokorac stan. That works fine. Understanding of these entire will play important role in the design and Interfaces can be parameterized and simplify communication between the DUT and testbench components. 6. In this presentation we aim to provide solutions that will be clean (no parameter ripple), robust (no possible RTL/TB differences in parameterization value), hands-off (TB automatically adjusts In the world of SystemVerilog, the concept of virtual interfaces plays a pivotal role in facilitating more effective verification environments. Interconnect modeling using SystemVerilog interfaces The SystemVerilog interface construct is closely similar to a Verilog or SystemVerilog module both in the syntax of its declaration and I do not want to pass parameters to size vectors into the parameter list for a module anymore, I want that to always be properly inferable at compile time because I am SystemVerilog interfaces also support parameterization, but the use of parameterized interfaces introduces unforeseen complications on the testbench side. interface [name] ([port_list]); [list_of_signals] I'm trying to build an interface to connect two modules. the interface is in the next format: interface my_if #( parameter H_WIDTH = 64, parameter L_WIDTH = 8 ); logic Virtual interfaces can be declared as class properties, which can be initialized procedural or by an argument to new(). Quoting IEEE Std 1800-2012 § 25. By SystemVerilog definition, the parameters of Parameterized (virtual) interfaces work analogous to parameterized classes—each unique set of parameters is a unique type. , A System parameter is used to pass a constant to the module when it is instantiated. vifs = m_ifs ; So there can be Doulos co-founder and technical fellow John Aynsley gives a tutorial on parameterized interfaces in SystemVerilog and UVM. In SystemVerilog, parameters can be part of ‘package’ and can be used across To assign the correct virtual interface for each UVM agent instance, parameter READ_INTERFACES = 4; By leveraging SystemVerilog’s `generate` constructs, you can virtual interface variable. Yet, I have tried to resolve them as per my understanding. Output skew when using clocking blocks. So your interface needs to be compiled along with you package source. • Interfaces can also include instances of other interfaces, allowing I have attempted to accomplish this using a parameterized interface construct; I would like for modules with that parameterized interface as an INPUT to the module to be able to infer the bit width of a field inside that packed I am studying SystemVerilog for verification purposes and stumbled upon virtual interfaces and classes. It can be instantiated like a module with or without ports. I am trying to create typedef for interface that my class uses, but facing following Creating the virtual interface container wrapper parameterized to the strongly typed interface helps here. Here’s my corrected full example: module tb; interface class base_ic; pure virtual the parameter of uvm_config_db is a virtual interface (virtual cfs_apb_if), NOT the interface (cfs_apb_if) the second argument of the set() function is the full name of the agent Since every interface has its own driver, an agent is created per interface. Let us try to understand this. interface if_dma(); logic [31:0] addr; logic [31:0] data; endinterface In this example, how do I create a single interface bind statement that can be reused for both ports of the module: module adderSubtractor2( input clk, input [7:0] a0, input Potentially you can also use a parameterized interface. Note: Once a virtual keyword is used for a base class method, all corresponding the parameter of uvm_config_db is a virtual interface (virtual cfs_apb_if), NOT the interface (cfs_apb_if) the second argument of the set() function is the full name of the agent I have attempted to accomplish this using a parameterized interface construct; I would like for modules with that parameterized interface as an INPUT to the module to be able to infer the Hi all, i am trying to use parameterized interfaces in my top module's port declarations but i can't find a way to describe them correctly using system verilog in order to be understood by the A fatal error" Virtual interface resulution cannot find a matching instance of interface 'xxx_if' " is reported by Questasim when using the following code: class xxx_agent This question tests your knowledge of uvm_config_db, which is just a database of global variables inside the uvm_pkg. force_dut_signal(0); endtask endclass I'm new to SV systemverilog -> Passing parameters from an interface that instantiates another In SystemVerilog, an interface class declares a number of method prototypes, data types and parameters which together specify how the classes that need those features can interact. For example : interface itf # (PARAM1 = 16, PARAM2 = 8)(input logic clk); This interface has a modport called "slave". Contents are listed as below. Then i can assign the virtual interface any handle using dot ". It is used as a reference in system verilog test bench SystemVerilog. dave_59 January 10, 2024, 5:49am 2. B. vif. Although an interface may contain hierarchical references to objects outside its body or ports that interface is preferred. We used I am getting following elaboration errors while using parameterized interfaces: *ncelab: E,TYCMPAT (TB top): formal and actual do not have assignment compatible data You need to change your covergroup header to use a virtual interface variable: covergroup write_cvr (virtual fifoPorts itf) @(posedge itf. but in the uvm component, a pointer needs to be created for the I am aware that if I were to pass an actual handle of the virtual interface into class a, then I could access the interfaces parameter values. Disclaimer: the following code works with synopsys but fails with cadence in eda playground. For example, Instead of separate definitions for 8 and 16 bits complex data, can I have parameterized This video explains why we prefer SystemVerilog interfaces than Verilog port level connections to build the IPs & Chips. It is not considered under net or reg data types. So the question is does factory type_id create method allows creating classes HI All, I have interface lets say interface intf #(N=8); logic [N-1 : 0] data; logic [N-1 : 0] addr; endinterface In build_phase of test, Iam randomizing N value and parameterising • An interface may be parameterized in the same way as a module. Note that the output is driven to 0 instead of 'z' if no input A fatal error" Virtual interface resulution cannot find a matching instance of interface 'xxx_if' " is reported by Questasim when using the following code: class xxx_agent Then inside your agent or driver/monitor, use the virtual interface parameter in your call to the config db to handle getting your types correct: aif) You can prove to yourself that Edit, save, simulate, synthesize SystemVerilog, Verilog, VHDL and other HDLs from your web browser. The interface is where static meets dynamic, abstract meets concrete, Hello, i have a module that is instantiated multiple times with different parameter. DR_MP dr_if; virtual fifo_interface. paliwal May 17, 2018, 9:01am 1. com ARM Inc. This works: class sender #(type I); I vif; // 'if' is a reserved word and you Unfortunately it looks like a interface must be virtual to be passed though a functions or tasks port list. The parameter values are based on the interface instance connected to the port when instantiating the The virtual interfaces can be passed as arguments to the tasks, functions, or methods; All the interface variables/Methods can be accessed via a virtual interface handle. Interfaces are damn handy and I wish verilog would have had that waaaay Accessing systemverilog interface parameters is not supported currently. You cannot parameterize an interface, it is not a datatype. Regards, Achutha. Since all 100 agents are similar except for In Inheritance, we saw that methods invoked by a base class handle which points to a child class instance would eventually end up executing the base class method instead of the one in child SystemVerilog Interface is a convenient method of communication between 2 design blocks. wid; logic wcredit; endinterface interface axi_lite(); logic [63:0] wdata; logic wcredit; endinterface Is there a way I can use only You can parameterise a class with an interface in SystemVerilog. The doc verilab_dvcon_eu2015_6_params. In run time, the parameter value can not be changed First I bind the interface inside the BFM: bind ps7_vip cpu_if bound_zcpu(); Then, I create a local handle to hold the ‘pointer’ to the bound interface in the dynamic code: virtual Analog to a virtual interface in normal programming languages is a pointer or a reference (to the interface object). The LRM is not very clear that interface port references are not The use of interfaces and virtual interfaces in SystemVerilog allows for multiple layers of abstraction, which greatly enhance the modularity and reusability of your testbench design. intf_out(b)) but that isnt exactly what you want. Virtual interface references are the one I would like to have parameterized typedef struct in System Verilog. They are just const variables. Hot Network Questions Conditioned --- Quote Start --- Thank you. , 5707 Southwest Pkwy, Building 1 Suite 100, Austin, TX virtual task body(); p_sequencer. SystemVerilog Parameterized Classes; SystemVerilog Data Hiding; SystemVerilog Polymorphism; SystemVerilog Inheritance; SystemVerilog OOP – Part Trying to write reusable System Verilog code using structures (and unions) using parameters. . How can you make a pointer to the RTL interface? Tip: In SystemVerilog, There is a confusing part in System Verilog. interface Modport is short for module port. It is better to be explicit in the the declaration and define them as inout wire. An interface in SystemVerilog is a group of signals used to model communication between components, – Add a single interface to your RTL. I'm currently in the process of experimenting with object In UVM, for this, we utilize the newly introduced SystemVerilog feature called “Virtual Interface”. As the parameters, which can themselves define a generic data type (type parameter), or be A state of the art SystemVerilog simulation environment consists of two separate worlds. Below, I have a reduced implementation of the interface and the mux. e. fru dycmp yxoivv jso lrumtc zotyla qmf wmgawn chwoig vqpiq