Xilinx SP605 - Manual (Page 23)

SP605 Hardware User Guide www.xilinx.com 23
UG526 (v1.8) September 24, 2012
Detailed Description
FPGA Design Considerations for the Configuration Flash
The SP605 has the P30 BPI flash connected to the FPGA dual use configuration pins and is
not shared. It can be used to configure the FPGA, and then controlled post-configuration
via the FPGA fabric. After FPGA configuration, the FPGA design can disable the
configuration flash or access the configuration flash to read/write code or data.
When the FPGA design does not use the configuration flash, the FPGA design must drive
the FLASH_OE_B pin High in order to disable the configuration flash and put the flash
into a quiescent, low-power state. Otherwise, the flash memory can continue to drive its
array data onto the data bus causing unnecessary switching noise and power
consumption.
For FPGA designs that access the flash for reading/writing stored code or data, connect
the FPGA design or EDK embedded memory controller (EMC) peripheral to the flash
through the pins defined in
Figure 1-5, page 17 .
References
See the Numonyx StrataFlash Embedded Memory Data Sheet for more information. [Ref 14]
In addition, see the Spartan-6 FPGA Configuration User Guide for more information. [Ref 2]
5. System ACE CF and CompactFlash Connector
The Xilinx System ACE CompactFlash (CF) configuration controller allows a Type I or
Type II CompactFlash card to program the FPGA through the JTAG port. Both hardware
and software data can be downloaded through the JTAG port. The System ACE CF
controller supports up to eight configuration images on a single CompactFlash card. The
configuration address switches allow the user to choose which of the eight configuration
images to use.
The CompactFlash (CF) card shipped with the board is correctly formatted to enable the
System ACE CF controller to access the data stored in the card. The System ACE CF
controller requires a FAT16 file system, with only one reserved sector permitted, and a
sector-per-cluster size of more than one (UnitSize greater than 512). The FAT16 file system
supports partitions of up to 2 GB. If multiple partitions are used, the System ACE CF
directory structure must reside in the first partition on the CompactFlash, with the
xilinx.sys
file located in the root directory. The xilinx.sys file is used by the System
ACE CF controller to define the project directory structure, which consists of one main
folder containing eight sub-folders used to store the eight ACE files containing the
configuration images. Only one ACE file should exist within each sub-folder. All folder
names must be compliant to the DOS 8.3 short file name format. This means that the folder
names can be up to eight characters long, and cannot contain the following reserved
characters: < > " / \ |. This DOS 8.3 file name restriction does not apply to the actual ACE
file names.
Other folders and files may also coexist with the System ACE CF project within the FAT16
partition. However, the root directory must not contain more than a total of 16 folder
and/or file entries, including deleted entries. When ejecting or unplugging the
CompactFlash device, it is important to safely stop any read or write access to the
CompactFlash device to avoid data corruption.