Intel® Quartus® Prime Pro Edition User Guide: Partial Reconfiguration

ID 683834
Date 7/31/2023
Public

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2.13.2. Clock-to-Data Ratio for Bitstream Encryption and Compression ( Intel® Arria® 10 or Intel® Cyclone® 10 GX Designs)

The following table lists the valid combinations of bitstream encryption and compression. The Clock-to-Data (CD) ratio is defined as the number of clock cycles that each cycle of data must remain valid before the next clock cycle. For example, a CD ratio of 4 means that the data must remain valid for 4 clock cycles before the next cycle. Enhanced decompression uses the same CD ratio as plain bitstreams (that is, with both encryption and compression off). When enhanced compression is enabled, always refer to x16 data width. If you use compression and enhanced compression together, the CD ratio follows the compression bitstream - 4. If you use plain and enhanced compression together, the CD ratio follows the plain bitstream - 1.
Table 8.  Valid Combinations and CD Ratio for Bitstream Encryption and Compression
Configuration Data Width AES Encryption Basic Compression CD Ratio
x8 Off Off 1
Off On 2
On Off 1
x16 Off Off 1
Off On 4
On Off 2
x32 Off Off 1
Off On 8
On Off 4

Use the exact CD ratio that the Valid combinations and CD Ratio for Bitstream Encryption and Compression table specifies for different bitstream types. The CD ratio for plain .rbf must be 1. The CD ratio for compressed .rbf must be 2, 4 or 8, depending on the width. Do not specify the CD ratio as the necessary minimum to support different bitstream types.