Ankita Kulkarni

Important topics on SystemVerilog (SV) needed in frontend of VLSI (Basics): [0] Difference b/w Verilog and SystemVerilog. Why SV is chosen for Verfication. [1] Difference between Mailbox and Queue. Is it possible to connect Generator and Driver with a Queue instead of Mailbox. [2] How race condition is avoided in Verilog. And what enhancements are present in SystemVerilog to counter the race condition. [3] Difference between clocking block and modport. Why modport is needed. Difference between clocking and program block. [4] Different event regions of SV. Difference between active and reactive region. What is the use of observed region. [5] Execution flow of assertion in the testbench. Difference between sequence and property. What is the role of semaphore. [6] What is the difference between Static and Dynamic testbench. Give examples. Is it always necessary to build a dynamic testbench. [7] Default input and output Skew. What is the need of using them. What is Synchronous driving. What is Sampling. [8] How error injection is provided in SV. What are callbacks and what are the different methods associated with it. [9] What is Class and an Object. Concept of Inheritance, Encapsulation and Polymorphism. [10] What is the difference b/w Shallow Copy and Deep Copy. Concept of Abstract Class, Concrete Class and Interface Class. [11] Difference between Multiple and Multilevel Inheritance. Difference b/w implement and extend. What is Composition and when it is used. [12] What is Singleton Class and what are the different types of design pattern. What function used as friend function in SV. How garbage collection is taking care in SV. [13] What are virtual function and where it is used. What is Virtual class. What are local and global variables. [14] Operator precedence in SV. Difference b/w Struct and Union. What is a linked list. [15] Write the code for driver with asynchronous reset. [16] Different Array reduction methods. Sorting of arrays. What are Packed structure. [17] What is a Diamond Problem and how to avoid it. Difference between static and dynamic casting. Parameterized classes. [18] How to make hierarchial connection with scoreboard from monitor. How to model a out of order transaction and in order transaction scoreboard. [19] Difference b/w bounded and unbounded mailbox. Can we use queue in generator and driver instead of mailbox. [20] What is Solve x before y constraint and when it is used. How to override a constraint. [21] What are Hard and Soft Constraints. What are weighted distribution constraints. [22] What is Pre randomize and Post randomize. What are the effects of constraint on and off mode. [23] Unique and Priority statement in SV. What are verilog full case and Parallel case and how unique and priority statements are solving the issue. [24] What is the need of interface in SV. Can we use physical interface for dynamic testbench and if so how? [25] Difference between for and foreach loop in SV.

167

2 Comments

Tips to clear any AMS Circuit Design Technical Interview? (1) Candidate should be thorough with what he or she has written in CV. What normally candidates do is they write more than what they have really done. This is not correct. If you do this you will be caught in interview and you will be in miserable situation during interview. e.g. If you have done Verification of some circuit, write clearly this. Don't write you have designed. (2) Remember, if you write too much that you have done so many things in short period, interviewer will not believe because it is not possible to do many things properly in short span. e.g. I have seen many CVs of RF Designers with five year experience mentioning too many things that they have done. In fact, some had mentioned they have done more than I have done in my more than 35 years of career in RF Design. (3) Be honest during interview. If you don't know please say I don't know. (4) Basically, in any AMS Circuit we use R, L, C, nMOS, pMOS. (In RF, other components are used. I will not discuss that now). You should be fully thorough with these components - how they work, types of these components, which parameters decide quality of these components, non-ideal model of these components, small-signal model, low-freq./high-frequency model of these components, etc.. If you don't know thoroughly about these components, you cannot become a good analog designer. (5) Connection of above components forms a circuit. To connect these components you use interconnects (different metal layers and vias). You should know these interconnect R, L, C models (transmission lines). Especially as frequency of operation of circuit increases this becomes very critical. (6) Thorough with writing Thevenin and Norton equivalent circuits. (7) Superposition theorem and control theory and network analysis. (8) Power Supply non idealities. (9) RLC Switching Circuits. (10) Remember, most of the circuits in analog and mixed-signal can be designed using switches and inverters. Be thorough with switches and inverters. (11) At least some basic knowledge in Analog Layout you must have so that you can mention how layout care to be taken in schematic itself. For example, which components need to be matched, where dummy devices should be placed, how much current major branches carry, where guard-rings to be placed, electro-migration, etc.. (12) Last but not least you should be thorough with use of at least one EDA tools, best is Cadence, for circuit simulation. You should know all possible simulations that can be done using Cadence. Best wishes! If you have any queries, please post here I will try to answer them or others may answer. 🙏🙏🙏🙏🙏

118

12 Comments

🧩 Why do we still say VLSI and not ULSI? As integration levels increased, we moved from SSI to MSI to LSI… eventually reaching VLSI (Very Large Scale Integration). Technically, the next stage was ULSI (Ultra Large Scale Integration) — but the term never really took off in industry usage. Why? Because VLSI became the accepted standard, covering everything from thousands to billions of transistors. Instead of changing the terminology again and again, the industry chose to evolve under the same name. For students and beginners, it’s a great example of how terms stick not just for accuracy, but for consistency. #VLSI #Semiconductors #ChipDesign #EngineeringStudents #TechInsights #WhyVLSI #ULSI #IntegratedCircuits #LearningJourney

133

2 Comments

Are you interested in understanding bare-metal development for microcontrollers? This mini-cookbook, authored by EmbeddedExpertIO, provides step-by-step instructions for writing bare-metal peripheral drivers for the STM32F4 family of microcontrollers. It covers essential topics like GPIO, timers, ADC, and UART. Each section includes practical code examples tested on the STM32F411 Nucleo . Save it for future use or reference 🤓 #Embedded_C #EmbeddedDev #EmbeddedSoftware

143

7 Comments

𝐈𝐧𝐝𝐢𝐚’𝐬 𝐒𝐞𝐦𝐢𝐜𝐨𝐧𝐝𝐮𝐜𝐭𝐨𝐫 𝐇𝐢𝐫𝐢𝐧𝐠 𝐒𝐮𝐫𝐠𝐞 𝐢𝐬 𝐑𝐞𝐝𝐞𝐟𝐢𝐧𝐢𝐧𝐠 𝐂𝐚𝐫𝐞𝐞𝐫𝐬! The semiconductor industry in India is experiencing an unprecedented hiring boom — gradually chipping away at IT placements and opening exciting opportunities for engineers across domains. 🔹 End-to-end hiring: RTL/SoC design, verification, embedded systems, manufacturing (process, packaging, yield). 🔹 Freshers’ salaries: ₹6–12 LPA (vs. ₹3–4 LPA in IT). 🔹 Aggressive campus recruitment from tier-2 & tier-3 colleges, not just IITs. 🔹 Internships: ₹40k–50k/month stipends to build hands-on chip design skills. 🔹 Hiring scale: ~12,000 freshers annually (up from 8,000 last year). 🔹 Career growth: Roles extend up to ₹20–120 LPA for architects & leaders. Fuelled by global supply chain shifts, EVs, telecom, defence, and government initiatives (DLI, PLI, ECMS), this hiring surge is reshaping student aspirations, especially in ECE and core engineering branches. With India projected to hit $103B semiconductor market by 2030, this is the right time for students and professionals to align their skills with VLSI, Embedded Systems, AI/ML hardware, and semiconductor manufacturing. The future is semiconductor — and India is powering ahead as a global hub! https://lnkd.in/gKtU5Gn2 #Semiconductor #VLSI #ChipDesign #EmbeddedSystems #Electronics #SoC #SemiconductorIndia #SemiconductorJobs #SemiconductorTalent #HiringTrends #Careers #ECE #Engineering #SemiconductorEcosystem #MakeInIndia #Innovation #ElectronicsManufacturing #FutureOfWork #AI #ML #Hardware #Manufacturing #IndiaSemiconductorMission

826

26 Comments

🔍 Why Is VLSI Recruitment So Challenging? 🤔 If you've ever tried hiring in the VLSI domain, you know it’s no walk in the park. From sourcing to onboarding, it’s a tough game—and here’s why: 💡 1. Niche Skill Set: VLSI isn't just another tech buzzword—it’s a highly specialized field requiring deep knowledge in areas like digital design, verification, physical design, and semiconductor fundamentals. Not every engineer can make the cut. 📉 2. Limited Talent Pool: The number of engineers trained in VLSI (especially hands-on experience) is much smaller compared to general software roles. Even fewer have experience with industry tools like Synopsys, Cadence, or Mentor. 🏫 3. Gap Between Academia & Industry: Universities often focus on theoretical aspects, while the industry demands practical expertise. This disconnect makes it harder for fresh grads to be job-ready, slowing down the hiring funnel. ⚙️ 4. Long Training Time: Even if you find good candidates, ramping them up takes months. Companies are cautious because hiring the wrong candidate in a chip design role is costly—literally. 📍 5. High Competition: Big players, startups, and fabs alike are all fishing from the same pond. Good candidates are often snapped up before you even get through the interview process. 🎯 What's the way forward? Partner closely with academic institutions for curriculum alignment Offer internships & co-op programs to create a future talent pipeline Invest in upskilling passionate engineers from adjacent domains Streamline and speed up your hiring process Let’s talk about how we can make VLSI hiring more sustainable and scalable. Are you facing the same challenges? Drop your thoughts below! 👇 #VLSI #Semiconductors #HiringChallenges #TalentAcquisition #ChipDesign #EDA #VLSIHiring #Recruitment

35

EMIR Checks in VLSI : As process nodes scale to 7nm, 5nm, and beyond, power delivery challenges become critical. EMIR (Electro-Migration & IR drop) analysis isn’t just a signoff formality—it’s the difference between reliable silicon and expensive respins. 🔹 IR Drop Static IR drop: Caused by average current → impacts DC voltage levels, reducing noise margin. Dynamic IR drop: Caused by instantaneous switching activity → leads to timing failures & setup/hold violations. 🔹 Electro-Migration (EM) High current density displaces metal atoms. Leads to void formation (open circuits) or hillocks (shorts). Reliability degradation follows Black’s Equation → failure rate ~ J^n * exp(-Ea/kT), where J is current density. 🔹 Why EMIR Checks Matter ✅ Ensure power integrity across standard cells & macros ✅ Capture voltage droop under realistic switching scenarios ✅ Validate reliability margins of interconnects & vias ✅ Provide lifetime projections for SoCs under actual workloads 🔹 Best Practices Use vector-based dynamic analysis for realistic IR stress conditions. Perform early in-design EMIR closure (not just signoff). Apply localized decap insertion & grid reinforcement where droop hotspots appear. Correlate RTL activity → gate-level simulation → signoff IR analysis for accuracy. With billion-transistor SoCs, EMIR is no longer just a backend task—it’s a design co-pilot. #VLSI #SoC #Semiconductors #ChipDesign #Reliability #EMIR

64

Data consistency when using DMA and CPU together: Ensuring data consistency between DMA and CPU is critical in embedded systems because both can access the same memory buffer—but the CPU may use cache, while the DMA always accesses main memory (RAM) directly. ✅ Why Inconsistency Happens The CPU reads/writes to/from cache. DMA reads/writes to/from RAM. If cache is not properly managed, CPU and DMA can see stale or unsynchronized data. 🧠 How to Ensure Data Consistency 1️⃣ Clean (Flush) the CPU Cache Use this before a DMA transfer from CPU → peripheral (DMA reads). Ensures dirty cache lines are written to RAM. Otherwise, DMA might read stale or partial data. 2️⃣ Invalidate the CPU Cache Use this after a DMA transfer from peripheral → CPU (DMA writes). Discards potentially stale CPU cache lines. Ensures CPU reads the updated data written by DMA to RAM. 3️⃣ Use Non-Cacheable Memory Allocate DMA buffers in non-cacheable memory region using: MMU/MPU configuration Special linker section dma_alloc_coherent() in Linux 🛑 This eliminates cache coherency problems but: May reduce performance for CPU Is used selectively (only for DMA buffers) 4️⃣ Ensure Cache Line Alignment DMA buffer must be aligned to cache line size (e.g., 32 or 64 bytes) Prevents false sharing and partial flush/invalidation 5️⃣ Check Cache Policy in MMU/MPU If buffer is marked write-back, cache maintenance is mandatory. If marked write-through or non-cacheable, issues are reduced. 6️⃣ Avoid Simultaneous Access Don't let CPU access buffer while DMA is active. Use synchronization: Flags, mutex, or semaphores Interrupts to signal DMA completion ✅ Best Practices: 1️⃣ Use dma_alloc_coherent() ➡️ Automatic non-cached, safe buffers 2️⃣ Align buffers to cache line size ➡️ Prevents partial cache line issues 3️⃣ Flush before DMA reads from buffer ➡️ Ensures DMA sees latest CPU writes 4️⃣ Invalidate after DMA writes to buffer ➡️ Ensures CPU sees latest DMA data 5️⃣ Avoid simultaneous access (CPU + DMA) ➡️ Prevents race conditions 6️⃣ Use memory barriers if needed ➡️ Ensures instruction ordering #linux #kernel #memory #embedded #systemdesign #learning

379

17 Comments

Why Every Young VLSI Engineer Should Master Scripting: The Secret to Working Smarter and Growing Faster 💡 Have you ever wondered how experienced VLSI engineers manage to breeze through massive datasets and complex reports? The secret lies in scripting—the ultimate productivity booster in the VLSI world. From parsing intricate timing reports to automating repetitive tasks, scripting languages like Python, Tcl, Perl, and Shell scripting enable engineers to work smarter, not harder. Here's why you should dive in: ✅ Save Time: Automate manual, time-consuming processes. ✅ Do More: Free up your schedule to focus on high-impact tasks. ✅ Stand Out: Show your value by solving problems efficiently and innovatively. ✅ Grow Faster: Contribute more to projects, build expertise, and accelerate your career growth. In a field like VLSI, where data drives decisions, your ability to manipulate and extract insights from tools can set you apart. Scripting is not just a skill; it’s a career catalyst. To all the budding VLSI engineers out there: Start scripting, start growing. Your future self will thank you. #VLSI #Scripting #Productivity #CareerGrowth #EngineeringTips #Semiconductor

142

2 Comments