FPGA configuration technology Most field-programmable gate arrays (FPGAs) store their configuration using ________ memory technology, which is ________. Choose the most accurate pairing.
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ADRAM, nonvolatile
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BSRAM, nonvolatile
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CSRAM, volatile
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DRAM, volatile
Answer
Correct Answer: SRAM, volatile
Explanation
Introduction / Context:FPGAs must load their configuration at power-up. The memory technology used determines whether the device is self-retaining (nonvolatile) or requires an external or internal configuration source each time it powers on. This has implications for boot time, security, and board architecture.
Given Data / Assumptions:
- We are discussing mainstream SRAM-based FPGAs (for example, Intel/Altera, Xilinx families).
- Nonvolatile families (for example, Flash-based) exist but are not the majority.
- Volatile memory loses its contents when power is removed.
Concept / Approach:Most high-performance FPGAs use static RAM (SRAM) cells to control routing switches and LUT contents. SRAM is volatile, so configuration vanishes at power-off. Therefore, a configuration image must be delivered at boot (via JTAG, a configuration flash, or a processor). Flash-based or antifuse FPGAs are nonvolatile but represent a different subset of the market and usually are not implied by the generic term in this question.
Step-by-Step Solution:
Identify common device families that use SRAM configuration cells.Recall that SRAM loses state without power; thus the FPGA needs a bitstream each boot.Map the pairings: SRAM ↔ volatile is the correct match.Conclude that “SRAM, volatile” is the most accurate general statement.Verification / Alternative check:Examine vendor datasheets: they state that configuration is loaded from external memory or via programming cable at power-up for SRAM-based devices.
Why Other Options Are Wrong:
- DRAM, nonvolatile: DRAM is also volatile and requires refresh.
- SRAM, nonvolatile: Contradiction; SRAM is volatile.
- RAM, volatile: Too generic; does not specify the specific technology normally used (SRAM).
Common Pitfalls:Assuming all FPGAs are nonvolatile; overlooking configuration security measures such as bitstream encryption used with volatile storage.
Final Answer:SRAM, volatile