Intel® Quartus® Prime Pro Edition User Guide: Design Recommendations
ID
683082
Date
3/28/2022
Public
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1.1. Using Provided HDL Templates
1.2. Instantiating IP Cores in HDL
1.3. Inferring Multipliers and DSP Functions
1.4. Inferring Memory Functions from HDL Code
1.5. Register and Latch Coding Guidelines
1.6. General Coding Guidelines
1.7. Designing with Low-Level Primitives
1.8. Recommended HDL Coding Styles Revision History
1.4.1.1. Use Synchronous Memory Blocks
1.4.1.2. Avoid Unsupported Reset and Control Conditions
1.4.1.3. Check Read-During-Write Behavior
1.4.1.4. Controlling RAM Inference and Implementation
1.4.1.5. Single-Clock Synchronous RAM with Old Data Read-During-Write Behavior
1.4.1.6. Single-Clock Synchronous RAM with New Data Read-During-Write Behavior
1.4.1.7. Simple Dual-Port, Dual-Clock Synchronous RAM
1.4.1.8. True Dual-Port Synchronous RAM
1.4.1.9. Mixed-Width Dual-Port RAM
1.4.1.10. RAM with Byte-Enable Signals
1.4.1.11. Specifying Initial Memory Contents at Power-Up
1.6.6.1. If Performance is Important, Optimize for Speed
1.6.6.2. Use Separate CRC Blocks Instead of Cascaded Stages
1.6.6.3. Use Separate CRC Blocks Instead of Allowing Blocks to Merge
1.6.6.4. Take Advantage of Latency if Available
1.6.6.5. Save Power by Disabling CRC Blocks When Not in Use
1.6.6.6. Initialize the Device with the Synchronous Load (sload) Signal
3.4.1. Apply Complete System-Centric Timing Constraints for the Timing Analyzer
3.4.2. Force the Identification of Synchronization Registers
3.4.3. Set the Synchronizer Data Toggle Rate
3.4.4. Optimize Metastability During Fitting
3.4.5. Increase the Length of Synchronizers to Protect and Optimize
3.4.6. Increase the Number of Stages Used in Synchronizers
3.4.7. Select a Faster Speed Grade Device
1.6.6.2. Use Separate CRC Blocks Instead of Cascaded Stages
Some designs optimize CRC to use cascaded stages (for example, four stages of 8 bits). In such designs, Intel® Quartus® Prime synthesis uses intermediate calculations (such as the calculations after 8, 24, or 32 bits) depending on the data width.
This design is not optimal for FPGA devices. The XOR cancellations that Intel® Quartus® Prime synthesis performs in CRC designs mean that the function does not require all the intermediate calculations to determine the final result. Therefore, forcing the use of intermediate calculations increases the area required to implement the function, as well as increasing the logic depth because of the cascading. It is typically better to create full separate CRC blocks for each data width that you require in the design, and then multiplex them together to choose the appropriate mode at a given time