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Platform Flash In-System Programmable Configuration PROMs
Design Security
The Xilinx in-system programmable Platform Flash PROM
devices incorporate advanced data security features to fully
protect the FPGA programming data against unauthorized
reading via JTAG. The XCFxxP PROMs can also be
programmed to prevent inadvertent writing via JTAG.
Table 3 and Table 4 show the security settings available for
the XCFxxS PROM and XCFxxP PROM, respectively.
Write Protection
The XCFxxP PROM device also allows the user to write
protect (or lock) a particular design revision or PROM option
settings. Write protection helps to prevent an inadvertent
JTAG instruction from modifying an area by write protecting
the area and by locking the erase instruction. The write-
protection setting can be cleared by erasing the protected
area. However, an XSC_UNLOCK instruction must first be
issued to the XCFxxP PROM to unlock the ISC_ERASE
instruction. Refer to the XCFxxP PROM BSDL file for the
XSC_UNLOCK and ISC_ERASE instructions.
Read Protection
The read protect security bit can be set by the user to
prevent the internal programming pattern from being read or
copied via JTAG. Read protection does not prevent write
operations. For the XCFxxS PROM, the read protect
security bit is set for the entire device, and resetting the read
protect security bit requires erasing the entire device. For
the XCFxxP PROM the read protect security bit can be set
for individual design revisions, and resetting the read
protect bit requires erasing the particular design revision.
Caution! The iMPACT software always issues a
XSC_UNLOCK when performing an Erase operation on an
XCFxxP PROM and, thus, always unlocks the write
protection.
Table 3: XCFxxS Device Data Security Options
Read/Verify
Inhibited
Program
Inhibited
Erase
Inhibited
Read Protect
Reset (default)
Set
3
Table 4: XCFxxP Design Revision Data Security Options
Read/Verify
Inhibited
Read Protect
Reset (default)
Write Protect
Program Inhibited
Erase Inhibited
Reset (default)
Set
Reset (default)
3
3
3
3
Set
Set
Reset (default)
Set
3
3
DS123 (v2.18) May 19, 2010
www.xilinx.com
Product Specification
4
XILINX [ XILINX, INC ]
