EP4SE360F35I4 Datasheet, PDF (384/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

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Chapter 10: Configuration, Design Security, and Remote System Upgrades in Stratix IV Devices
Configuration Data Decompression
Configuration Data Decompression
Stratix IV devices support configuration data decompression, which saves
configuration memory space and time. This feature allows you to store compressed
configuration data in configuration devices or other memory and transmit this
compressed bitstream to Stratix IV devices. During configuration, the Stratix IV
device decompresses the bitstream in real time and programs its SRAM cells.
1 Preliminary data indicates that compression typically reduces the configuration
bitstream size by 30% to 55% based on the designs used.
Stratix IV devices support decompression in the FPP (when using a MAX II device or
microprocessor + flash), fast AS, and PS configuration schemes. The Stratix IV
decompression feature is not available in the JTAG configuration scheme.
In PS mode, use the Stratix IV decompression feature because sending compressed
configuration data reduces configuration time.
When you enable compression, the Quartus II software generates configuration files
with compressed configuration data. This compressed file reduces the storage
requirements in the configuration device or flash memory, and decreases the time
needed to transmit the bitstream to the Stratix IV device. The time required by a
Stratix IV device to decompress a configuration file is less than the time needed to
transmit the configuration data to the device.
There are two ways to enable compression for Stratix IV bitstreams—before design
compilation (in the Compiler Settings menu) and after design compilation (in the
Convert Programming Files window).
To enable compression in the project’s Compiler Settings menu, follow these steps:
1. On the Assignments menu, click Device to bring up the Settings dialog box.
2. After selecting your Stratix IV device, open the Device and Pin Options window.
Stratix IV Device Handbook
Volume 1
September 2012 Altera Corporation