FPGA Configuration Shift Chain for Fast Multi-Bitstream Switching
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Solution Overview
Problem
FPGA chips face a long and inefficient process when switching between different user designs, requiring re-download of bitstreams and restarts, making them unsuitable for high-speed or frequent function changes.
Innovation Solution
An FPGA design utilizing a configuration shift chain with multi-bitstream storage configuration bits and a bitstream control circuit, allowing for sequential cascading and switching of configuration bitstreams without re-downloading, enabling high-speed switching between logic functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bitstreams are re-downloaded from off-chip when switching user designs, then the FPGA can implement different functions, but the switching process becomes time-consuming and inefficient
Solution Approach 1:
The patent stores multiple bitstreams in advance within the configuration shift chain's storage elements (flip-flops and latches) before switching is needed. When a function switch is required, the pre-stored bitstream is already available in the chain, eliminating the need for time-consuming re-downloading from off-chip memory. This preliminary storage of multiple configuration bitstreams resolves the contradiction by enabling fast function switching while maintaining adaptability.
2Adaptability or versatility
If the FPGA is restarted to implement a new function, then the configuration can be updated, but the process becomes complex and time-consuming
Solution Approach 1:
The patent introduces dynamic control mechanisms including a mode selection multiplexer and control logic that can switch between different operational modes (normal configuration mode and fast switch mode). In fast switch mode, the system can update functions without full restart by controlling the configuration shift chain to load and activate pre-stored bitstreams. This dynamic switching capability reduces both the complexity and time of configuration updates while maintaining full adaptability.
3Speed
If multiple bitstreams are stored in the configuration shift chain, then fast switching is enabled, but the device complexity increases
Solution Approach 1:
The patent enhances the universal functionality of the configuration shift chain by enabling it to serve multiple purposes: normal single-bitstream configuration, multi-bitstream storage, and fast switching between bitstreams. By adding control logic and mode selection capabilities to the existing shift chain structure, the system achieves multi-functionality that supports both traditional configuration operations and accelerated switching operations, thereby enabling fast switching without proportionally increasing complexity.
Data Source
AI summary
A field-programmable gate array (FPGA) for using a configuration shift chain to implement a multi-bitstream function includes a bitstream control circuit, a multi-bitstream configuration shift chain and a configurable module. The FPGA enables multi-bitstream storage configuration bits to latch configuration bitstreams by adjusting a circuit structure of a multi-bitstream configuration shift chain in a combination of a control logic of a bitstream control circuit for the multi-bitstream configuration shift chain, and outputs one latched configuration bitstream from a configuration output terminal to a configurable module through each multi-bitstream storage configuration bit as required, so that the configurable module implements a logic function corresponding to the configuration bitstream outputted by the multi-bitstream configuration shift chain. By switching output of different configuration bitstreams, the FPGA can perform a plurality of times of high-speed switching to implement different logic functions without downloading bitstreams from an off-chip.