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Xilinx is now officially establishing the readback specification of
the XC4000, XC4000D and XC4000E to be 1MHz-2MHz. The performance level
for the readback feature has never been officially specified, although
it had been described in a published application note to be 10KHz-1MHz
(
XAPP
015.000 "Using the XC4000 Readback Capability"). Establishing
this specification improves performance of the device and allows a higher
performance of this powerful feature. Xilinx believes that establishing
this specification will adversely affect very few users. However, for those
that are affected, Xilinx can provide silicon that meets 10KHz-1MHz operation.
Contact your Xilinx sales representative for more information.
Also, this change will require a software patch to the X-Checker accessory,
which will adjust its operating frequency to meet the new specification.
This patch is now on the Xilinx BBS (PC only) and FTP site. Versions are
available for the PC,
Sun
workstation, and HP
workstation. The existing X-Checker operation can be used, however a small
chance exists that the current X-Checker may register erroneous readback
errors. If readback errors are encountered, they are most likely indicative
of X-Checker operating outside of the specification range, and not a reflection
of the configuration data integrity. If you encounter a readback issue,
please contact your Xilinx sales representative
or the Xilinx hotline.
Updated specifications have been added to the
XC4000 Series Data sheet (v1.04).
Trch and Trcl are the key parameters affected and they can be found on
page 4-81. This affects only the XC4000 (including the "D") and
XC4000E families, and not the XC4000A, XC4000H, XC4000EX or any other Xilinx
product families.
9/15/96 XCU 099601