Professional-grade RTL development framework built entirely with open-source tools
RTL Design Sherpa represents a comprehensive approach to modern hardware design, providing a complete ecosystem that bridges the gap between academic learning and professional IC development. Built exclusively with open-source tools, the framework delivers industry-standard design practices, automated verification flows, and production-quality IP blocks.
The framework addresses a critical need in the digital design community: access to professional-grade development tools and methodologies without the barrier of expensive commercial EDA licenses. By leveraging proven open-source tools like Verilator, Verible, and CocoTB, RTL Design Sherpa creates a development environment that rivals commercial solutions while maintaining complete transparency and extensibility.
The framework is built on four core principles that reflect modern industry practices:
1. Verification-Driven Development Every RTL module includes comprehensive test suites from the outset. This isn't an afterthought—it's the foundation of the development process. Each module includes:
- Unit tests covering all parameter combinations
- Edge case testing and boundary condition validation
- Performance characterization across frequency ranges
- Protocol compliance verification where applicable
2. Automated Quality Assurance Code quality is maintained through automated tools integrated into the development flow:
- Verible Integration: Automated linting and style checking ensure consistent code quality
- Regression Testing: Automated nightly runs with comprehensive reporting
- Coverage Analysis: Both code and functional coverage tracking
- Documentation Generation: Automated waveform and timing diagram creation
3. Modular IP Architecture The framework emphasizes reusable, parameterized IP blocks:
- Interface-Based Design: Clean abstraction using SystemVerilog interfaces
- Parameter-Driven Configuration: Modules adapt to various system requirements
- Hierarchical Organization: Clear separation of concerns and dependencies
- Protocol Compliance: Full adherence to industry standards (AMBA, etc.)
4. Professional Development Practices The toolchain and workflows mirror those used in commercial IC development:
- Version Control Integration: Git-based workflows with automated testing
- Continuous Integration: Automated testing on code changes
- Documentation Standards: Comprehensive module documentation with examples
- Performance Analysis: Timing, area, and power characterization
- Verilator: High-performance simulation engine with VCD/FST waveform generation
- GTKWave: Professional waveform viewer with pre-configured signal groups
- Verible: Industry-standard SystemVerilog parsing, linting, and formatting
- CocoTB: Python-based verification with full SystemVerilog integration
- pytest: Test discovery, execution, and reporting infrastructure
- Custom VIP: Protocol-specific verification IP for AMBA and other standards
- Python 3.8+: Automation, code generation, and analysis scripts
- Makefile Integration: Standardized build and test execution
- JSON Configuration: Flexible tool and test configuration management
The common library provides fundamental building blocks organized by function:
- Advanced Adders: Brent-Kung parallel prefix, carry-select, and optimized ripple carry
- High-Performance Multipliers: Wallace tree and Dadda implementations with configurable pipelines
- Division Circuits: Non-restoring and SRT division algorithms
- Mathematical Functions: Square root, logarithm approximations, and trigonometric functions
- FIFO Implementations: Synchronous, asynchronous, and multi-clock domain variants
- Memory Controllers: SRAM interfaces with configurable timing and width
- Shift Registers: Linear feedback (LFSR) and standard shift register implementations
- Content Addressable Memory: Fully associative CAM with configurable depth
- Arbitration: Round-robin, weighted, and priority-based arbiters
- Encoding/Decoding: Priority encoders, gray code converters, and Hamming ECC
- Clock and Reset Management: ICG modules, reset synchronizers, and CDC utilities
- Protocol Bridges: Interface converters and protocol adapters
- CRC Engines: Generic CRC calculation supporting 300+ industry standards
- Data Integrity: Parity checkers, error detection, and correction circuits
- Communication Interfaces: UART, SPI, I2C controllers with configurable parameters
Complete implementation of ARM AMBA specifications:
- APB Masters: Command/response interfaces with FIFO buffering
- APB Slaves: Register interfaces with configurable address decoding
- APB Interconnect: Multi-master/multi-slave crossbar with weighted arbitration
- APB Bridges: Protocol conversion and clock domain crossing
- AXI4 Masters: Read/write masters with dual skid buffer architecture
- AXI4 Slaves: Configurable response generation and address decoding
- Performance Optimizations: Pipeline stages and buffer management for high throughput
- Advanced Features: Outstanding transaction tracking and QoS support
- Simplified Protocol: Register-optimized masters and slaves
- Configuration Registers: Standardized register map implementation
- Error Handling: Comprehensive error detection and reporting
- Integration Support: Easy connection to APB and other protocols
- Streaming Masters/Slaves: High-throughput data transfer interfaces
- Flow Control: Backpressure handling and buffer management
- Sideband Signals: Full support for TID, TDEST, TUSER, and TSTRB
- Performance Optimization: Configurable buffer depths and pipeline stages
- GAXI Buffers: Generic AXI infrastructure for skid buffers and FIFOs
- Monitoring: Protocol compliance checkers and performance analyzers
- Arbitration: Advanced round-robin and weighted arbitration schemes
- System Integration: Address decoders, protocol bridges, and interconnects
The framework employs a sophisticated verification methodology built on CocoTB:
class ModuleTestbench:
"""Professional testbench structure"""
def __init__(self, dut):
self.dut = dut
self.clock = Clock(dut.clk, 10, units="ns")
self.drivers = self._create_drivers()
self.monitors = self._create_monitors()
self.scoreboards = self._create_scoreboards()
async def reset_sequence(self):
"""Standardized reset procedure"""
async def configure(self, **params):
"""Parameter-driven configuration"""
async def run_test_sequence(self, test_vector):
"""Execute parameterized test"""Custom verification IP provides:
- Protocol Drivers: Automated stimulus generation for AMBA protocols
- Intelligent Monitors: Transaction-level monitoring with compliance checking
- Scoreboards: Expected vs. actual result comparison with detailed reporting
- Coverage Collectors: Functional coverage tracking and analysis
- Directed Testing: Specific test cases targeting known scenarios
- Constrained Random: Intelligent stimulus generation with realistic constraints
- Protocol Compliance: Automated checking against specification requirements
- Performance Testing: Bandwidth, latency, and stress testing scenarios
# Example regression configuration
{
"test_suites": {
"nightly_regression": {
"common_modules": ["counter", "fifo", "arbiter", "crc"],
"amba_protocols": ["apb_master", "axi4_slave", "axis_master"],
"integration_tests": ["multi_master_system", "protocol_bridge"]
}
},
"configurations": {
"parameter_sweep": True,
"randomize_seeds": True,
"coverage_collection": True
}
}- Automated Reports: HTML and text-based test result summaries
- Coverage Analysis: Line, branch, and functional coverage tracking
- Performance Metrics: Frequency characterization and resource utilization
- Trend Analysis: Historical performance and quality tracking
Automated RTL generation for complex arithmetic:
# Generate optimized 64-bit Brent-Kung adder
python3 bin/math_generate.py --type brent_kung --buswidth 64 --path ./generated/
# Generate Wallace tree multiplier
python3 bin/math_generate.py --type wallace_fa --buswidth 32 --path ./generated/- AXI Split Calculator: Precise calculation of AXI transaction boundary splitting
- Interface Flattener: Convert SystemVerilog interfaces to Verilator-compatible signals
- Dependency Analyzer: Module instantiation and hierarchy analysis
- UML Generator: Automated architecture diagram generation
# Comprehensive code quality check
python3 bin/lint_wrap.py --format --lint
# Project-wide analysis
python3 bin/struct_test_script.py --analyze --report- Wavedrom Integration: VCD to timing diagram conversion
- Markdown Processing: Automated documentation formatting and linking
- Performance Visualization: Automated chart and graph generation
# Single module test
python3 bin/ipynb/run_test_wrap.py --test val/unit_common/test_counter --tag verification
# Full regression suite
python3 bin/ipynb/run_test_wrap.py --testlist nightly_regression --randomizeThe framework provides hooks and scripts for integration with continuous integration systems:
- Pre-commit Hooks: Automated quality checking before code commits
- Regression Triggers: Automatic testing on code changes
- Performance Monitoring: Continuous performance characterization
- Documentation Updates: Automatic documentation regeneration
The framework has been characterized across multiple FPGA and ASIC technologies:
| Module Category | Frequency Range | Resource Usage | Typical Applications |
|---|---|---|---|
| Basic Logic | 100-800 MHz | Minimal | Counters, registers, simple control |
| Advanced Arithmetic | 200-600 MHz | Moderate | DSP, mathematical operations |
| Memory Interfaces | 300-500 MHz | High | DDR controllers, cache interfaces |
| Protocol Bridges | 200-400 MHz | Variable | System integration, protocol conversion |
| Streaming Interfaces | 400-600 MHz | Moderate | Video, networking, high-throughput data |
Regular synthesis characterization across multiple tools ensures optimal results:
- Area Optimization: Resource-constrained implementations available
- Speed Optimization: Pipeline variants for high-frequency operation
- Power Optimization: Clock gating and power-aware design techniques
- Technology Portability: Tested across FPGA and ASIC synthesis flows
- Line Coverage: >95% across all RTL modules
- Branch Coverage: >90% with focus on critical decision points
- Functional Coverage: 100% for protocol compliance requirements
- Parameter Coverage: Comprehensive testing across all configuration options
- Unit Test Coverage: Every module includes comprehensive test suites
- Integration Testing: Multi-module systems tested with realistic scenarios
- Protocol Compliance: Full specification compliance verification
- Performance Validation: Timing and resource utilization characterized
The framework serves as an excellent platform for:
- Digital Design Courses: Complete ecosystem for learning RTL development
- Verification Training: Professional-grade verification methodologies
- Industry Preparation: Hands-on experience with real-world tools and practices
- Research Projects: Foundation for hardware architecture research
Industry professionals use the framework for:
- IP Development: Starting point for commercial IP development
- Prototype Development: Rapid development of proof-of-concept designs
- Tool Evaluation: Comparing open-source vs. commercial tool capabilities
- Skill Development: Learning new verification techniques and methodologies
Startup companies leverage the framework for:
- Rapid Prototyping: Quick development of hardware IP
- Cost-Effective Development: Eliminating expensive EDA tool licenses
- Team Training: Standardized development practices and workflows
- IP Portfolio Building: Foundation for developing valuable IP assets
- PCIe Controllers: Complete PCIe endpoint and root complex implementations
- Ethernet MAC: 1G/10G Ethernet media access controllers
- USB Controllers: USB 2.0/3.0 device and host controllers
- DDR Interfaces: Complete DDR3/DDR4/DDR5 memory controller implementations
- Formal Verification: Integration with open-source formal verification tools
- Coverage-Driven Verification: Automated test generation based on coverage holes
- System-Level Testing: Complete SoC verification environments
- Performance Modeling: Cycle-accurate performance analysis tools
- Synthesis Integration: Direct integration with open-source synthesis tools
- Place and Route: Integration with open-source P&R flows
- Timing Analysis: Static timing analysis integration
- Power Analysis: Power consumption analysis and optimization tools
- Module Contributions: Community-contributed IP blocks
- Verification IP: Shared verification components and testbenches
- Tool Development: Community-developed analysis and automation tools
- Documentation: Community-maintained tutorials and examples
- University Collaborations: Partnerships with academic institutions
- Industry Mentorship: Professional guidance for student projects
- Certification Programs: Structured learning paths with validation
- Conference Presentations: Regular updates and presentations at industry events
RTL Design Sherpa represents a fundamental shift in how hardware development is approached, democratizing access to professional-grade tools and methodologies while maintaining the quality and rigor expected in commercial IC development. The framework continues to evolve, driven by both community contributions and industry needs, ensuring its relevance and value for both educational and professional applications.
For detailed implementation guides, tutorials, and API documentation, explore the comprehensive documentation sections linked throughout this overview.