SoCs (System on Chips) are complex designs with heterogeneous modules (CPU, memory, etc.) integrated in them. Verification is one of the important stages in designing an SoC. Verification is the process of checking if the transformation from architectural specification to design implementation is correct. Verification involves creating the following components: (i) a testplan that identifies the conditions to be verified, (ii) a testcase that generates the stimuli to verify the conditions identified, and (iii) a test-bench that applies the stimuli and monitors the output from the design. Verification consumes upto 70% of the total design time. This is largely due to the complex and manual nature of the verification task. To reduce the time spent in verifying the design, the components used for verification can be generated automatically or created at an abstract level (to reduce the complexity) and reused. In this work we present a methodology to synthesize testcases from reusable code segments and abstract specifications. Our methodology consists of the following major steps: (i) identifying the structure of testcases, (ii) identifying code segments of testcases that can be reused from one SoC to another, (iii) identifying properties of an SoC and its modules that can be used to synthesize the SoC specific code segments of the testcase, and (iv) proposing a synthesizer that uses the code segments, the properties and the abstract specification to synthesize testcases. We discuss two specific classes of testcases. These are testcases for verifying the memory modules and the testcases for verifying the data transfer modules. These are considered since they form a significantly large subset of the device functionality. We implement a prototype testcase generator and also present an example to illustrate the use of methodology for each of these classes. The use of our methodology enables (i) the creation of testcases automatically that are correct by construction and (ii) reuse of the testcase code segments from one SoC to another. Some of the properties (of the modules and the SoC) presented in our work can be easily made part of the architectural specification, and hence, can further reduce the effort needed to create them.

With industry expectations of billions of Internet-connected things, commonly referred to as the IoT, we see a growing demand for high-performance on-chip bus architectures with the following attributes: small scale, low energy, high security, and highly configurable structures for integration, verification, and performance estimation. Our research thus mainly focuses on addressing these key problems and finding the balance among all these requirements that often work against each other. First of all, we proposed a low-cost and low-power System-on-Chips (SoCs) architecture (IBUS) that can frame data transfers differently. The IBUS protocol provides two novel transfer modes – the block and state modes, and is also backward compatible with the conventional linear mode. In order to evaluate the bus performance automatically and accurately, we also proposed an evaluation methodology based on the standard circuit design flow. Experimental results show that the IBUS based design uses the least hardware resource and reduces energy consumption to a half of an AMBA Advanced High-Performance Bus (AHB) and Advanced eXensible Interface (AXI). Additionally, the valid bandwidth of the IBUS based design is 2.3 and 1.6 times, respectively, compared with the AHB and AXI based implementations. As IoT advances, privacy and security issues become top tier concerns in addition to the high performance requirement of embedded chips. To leverage limited resources for tiny size chips and overhead cost for complex security mechanisms, we further proposed an advanced IBUS architecture to provide a structural support for the block-based AES algorithm. Our results show that the IBUS based AES-encrypted design costs less in terms of hardware resource and dynamic energy (60.2%), and achieves higher throughput (x1.6) compared with AXI. Effectively dealing with the automation in design and verification for mixed-signal integrated circuits is a critical problem, particularly when the bus architecture is new. Therefore, we further proposed a configurable and synthesizable IBUS design methodology. The flexible structure, together with bus wrappers, direct memory access (DMA), AES engine, memory controller, several mixed-signal verification intellectual properties (VIPs), and bus performance models (BPMs), forms the basic for integrated circuit design, allowing engineers to integrate application-specific modules and other peripherals to create complex SoCs.