- #Design size exceeds modelsim pe student edition verification
- #Design size exceeds modelsim pe student edition code
- #Design size exceeds modelsim pe student edition simulator
It may already be included with the default libraries that come with your simulator.
#Design size exceeds modelsim pe student edition simulator
The OSVVM library can be used with any simulator that supports VHDL-2008. The simulation will be stopped when all the functional coverage events that we are monitoring have occurred. We will monitor these events in our main testbench sequencer process. A functional coverage point could mean for example a simultaneous read and write, or that the FIFO is filled at least once. If the two FIFO implementations behave differently at any time, an assertion failure will cause the simulation to terminate with an error.įinally, we will collect functional coverage data by observing the transactions that are going to and coming from the DUT. This process will be solely responsible for doing this comparison on every clock cycle by using assert statements.
![design size exceeds modelsim pe student edition design size exceeds modelsim pe student edition](http://1.bp.blogspot.com/-X7-OR8ht9Ag/Uk-th0V5CNI/AAAAAAAAAOI/WQVC0qfK_Fk/s1600/5.png)
We will compare the output from the DUT with the output from the behavioral model in a separate process. This gives us the freedom to use advanced VHDL programming features for creating it.
![design size exceeds modelsim pe student edition design size exceeds modelsim pe student edition](https://docplayer.net/docs-images/46/21149659/images/page_1.jpg)
Unlike the DUT, the behavioral model doesn’t have to be synthesizable. This is a FIFO which is implemented differently from the ring buffer that is used in the DUT, but still has the same interface. There will be a behavioral model in parallel with the DUT. We will assert the read enable signal in bursts which last for a random number of clock cycles. Similarly, we will perform reads at random. The input data will be set to a random value on every clock cycle, and the strobes on the write enable input will be of random duration. We will perform random write transactions at the input side of the DUT. The image below shows the main concept of the testbench that we are about to create. Let’s go through the testing strategy before we start implementing anything at all. The DUT generics will be mapped to the following values:
#Design size exceeds modelsim pe student edition code
The instantiation is trivial, so I will omit the code for now, but it can be downloaded later in this article. We will instantiate the DUT in the testbench by using the entity instantiation method. After all, this article is about the testbench, not the ring buffer FIFO. We’re going to treat the DUT as a black box, meaning that we won’t assume any knowledge of how the DUT is implemented. The entity of the ring buffer module is shown in the code above. Rd_data : out std_logic_vector(RAM_WIDTH - 1 downto 0) įill_count : out integer range RAM_DEPTH - 1 downto 0 Wr_data : in std_logic_vector(RAM_WIDTH - 1 downto 0) We’re going to create a proper testbench for the ring buffer FIFO that uses constrained random verification. We created a ring buffer FIFO in the previous article on this blog, but we didn’t create a self-checking testbench to verify the correctness of the module. I’m going to dive right into an example to better explain how a constrained random testbench differs from the classic testbench, which uses directed tests. I recommend visiting the OSVVM GitHub page to learn more about the features of this library. We are particularly interested in the RandomPkg and CoveragePck, which we will be using in this article.
#Design size exceeds modelsim pe student edition verification
Open Source VHDL Verification Methodology (OSVVM) is a free VHDL library which includes a number of convenient packages for creating constrained random testbenches.
![design size exceeds modelsim pe student edition design size exceeds modelsim pe student edition](https://salonfasr473.weebly.com/uploads/1/2/5/3/125318647/708507992.jpg)
The goal is to reach functional coverage of a number of predefined events through random interaction with the DUT.
![design size exceeds modelsim pe student edition design size exceeds modelsim pe student edition](https://i.stack.imgur.com/XhOHV.jpg)
Constrained random verification is a testbench strategy that relies on generating pseudo-random transactions for the device under test (DUT).