Intel® Quartus® Prime Standard Edition User Guide: Partial Reconfiguration Intel® FPGA IP

ID 683404
Date 4/18/2019

1.7. Clock-to-Data Ratio (CD Ratio)

The proper clock-to-data ratio (CD Ratio) is critical for partial reconfiguration. A proper CD Ratio ensures that the data being processed synchronizes during the PR operation whether you are using compression, encryption, or both, or neither.

The Control Block (CB) interface receives data and sends it during a PR event with the CD Ratio you specify when you instantiate the Partial Reconfiguration IP core.

Table 2.  Valid combinations and CD Ratio for Bitstream Encryption and Compression for Stratix® V Devices
Compressed Encrypted CD Ratio
Off Off 1
Off On 2
On Off 4
On On 4

CD Ratio for the PR IP core in Stratix® V designs must be exact for the bitstream type. CD Ratio for plain Programmer Object File (POF) must be 1. CD Ratio for compressed POF 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.

Note: Standard encryption uses the same CD Ratio setting as a plain, uncompressed bitstream.