EN025 Datasheet, PDF (1/2 Pages) Xilinx, Inc – Spartan-3E XC3S250E FPGA Errata

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Spartan-3E XC3S250E FPGA
Errata
EN025 (v1.0) October 19, 2007
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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.
Table 1: Advisories and Software Update
Advisory
ISE™ Software Version
“Persist I/O Conflict”
10.1
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 Table 2. No other address lines will be affected by Persist.
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
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EN025 (v1.0) October 19, 2007
www.xilinx.com
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Errata Notice