Configuration Handbook - Kamami.pl

Configuration Features1 When using FPP mode, the intelligent host must provide a DCLKthat is 4× the data rate. Therefore, the configuration data must bevalid for four DCLK cycles.The decompression feature supported by Stratix II and Stratix II GXdevices is different from the decompression feature in enhancedconfiguration devices (EPC16, EPC8, and EPC4 devices), although theyboth use the same compression algorithm. The data decompressionfeature in the enhanced configuration devices allows them to storecompressed data and decompress the bitstream before transmitting it tothe target devices. When using Stratix II and Stratix II GX devices in FPPmode with enhanced configuration devices, the decompression feature isavailable only in the enhanced configuration device, not the Stratix II orStratix II GX device.In PS mode, use the Stratix II or Stratix II GX decompression featurebecause sending compressed configuration data reduces configurationtime. Do not use both the Stratix II or Stratix II GX device and theenhanced configuration device decompression features simultaneously.The compression algorithm is not intended to be recursive and couldexpand the configuration file instead of compressing it further.When you enable compression, the Quartus II software generatesconfiguration files with compressed configuration data. This compressedfile reduces the storage requirements in the configuration device or flashmemory, and decreases the time needed to transmit the bitstream to theStratix II or Stratix II GX device. The time required by a Stratix II orStratix II GX device to decompress a configuration file is less than thetime needed to transmit the configuration data to the device.There are two ways to enable compression for Stratix II and Stratix II GXbitstreams: before design compilation (in the Compiler Settings menu)and after design compilation (in the Convert Programming Fileswindow).To enable compression in the project’s compiler settings, select Deviceunder the Assignments menu to bring up the Settings window. Afterselecting your Stratix II or Stratix II GX device, open the Device & PinOptions window, and in the General settings tab enable the check box forGenerate compressed bitstreams (as shown in Figure 7–1).7–6 Altera CorporationStratix II Device Handbook, Volume 2 May 2007