EN025 (v1.0) October 19, 2007 www.xilinx.com 1
Errata Notice
© 2007 Xilinx, Inc. All rights reserved. All Xilinx trademarks, registered trademarks, patents, and disclaimers are as listed at http://www.xilinx.com/legal.htm.
All other trademarks and registered trademarks are the property of their respective owners. All specifications are subject to change without notice.
Hardware Errata
There are no errata for the Spartan-3E XC3S250E FPGA.
See the “Production Stepping” section in the data sheet for additional information:
http://www.xilinx.com/bvdocs/publications/ds312.pdf
Advisories
This section advises designers of any potential software changes that may affect their XC3S250E FPGA applications.
Table 1 summarizes the advisories and indicates which software update will correct the issue.
Persist I/O Conflict
Applications affected
This issue affects applications that use the Persist option in the Bitstream Generator and use configuration address
pins A20-A23 in the design. The current software allows this conflict between Persist and user functionality, so the
user must be careful to avoid this situation. Persist is set to No by default, and can be enabled by Persist:Yes at the
command line or "Allow SelectMAP Pins to Persist" in the Project Navigator. Persist is most commonly used to allow
Readback through the Slave Parallel (SelectMAP) configuration port after configuration. This issue affects
XC3S250E devices in the CP(G)132, PQ(G)208, and FT(G)256 packages. This does not affect XC3S250E devices
in the VQ(G)100 and TQ(G)144 packages.
Description
Using the Persist option in the Bitstream Generator, and setting the Mode pins to a parallel configuration mode
including Byte Peripheral Interface (BPI) or Slave Parallel (SelectMAP) modes, will retain the parallel configuration
interface. This is useful when configuring in the SelectMAP mode to allow configuration commands such as
Readback to be used after configuration. The pins affected by Persist cannot be used in the design, including M[2:0],
CCLK, D[7:0], INIT_B, CSI_B, RDWR_B, and BUSY, as described in the documentation.
The issue is that Persist will block four additional specific dual-purpose I/Os from use by the design when Persist is
enabled and the Mode pins are set for a parallel configuration mode. These pins become disconnected from the
user design when Persist is used and therefore cannot be used by the design. If unused in the design, these pins will
have a weak pull-down resistor when Persist is used. If used in the design, the pin state is design-dependent.
The affected I/Os are the highest order address lines for the configuration interface, A20-A23. The associated pin
numbers are shown in Ta bl e 2 . No other address lines will be affected by Persist.
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Spartan-3E XC3S250E FPGA
Errata
EN025 (v1.0) October 19, 2007
00
Errata Notice
Table 1: Advisories and Software Update
Advisory ISE™ Software Version
“Persist I/O Conflict” 10.1
Table 2: Affected Pins
Package A20 A21 A22 A23
CP(G)132 M10 N10 M9 N9
PQ(G)208 P97 P96 P94 P93
FT(G)256 N12 P12 P11 R11
