Q:

Hi,

For the Spartan-II, the preconfiguration pullup resistors were selected
by the M2 configuration pin. What about for the Spartan-3?

My new design has to connect an ARM7TDMI bus to the SPARTAN-3. I need to
make sure my ucLinux will boot correctly, and so make sure about the IO
pins states of the SPARTAN-3 on the poweron.

Regards,
Laurent

-----------

A:

Like Virtex-II and Virtex-II Pro, the Spartan-3 FPGA pre-configuration
pull-up resistors are controlled by the HSWAP_EN pin.

0 = Enables weak pull-up resistors on all pins not actively involved in the
configuration process.

1 = No pull-up resistors during configuration.

After configuration, this pin is not used and should be kept at a logic 0 or
1.

See page 13 of the Spartan-3 data sheet (Module 4, Pinouts) for more
information.
http://direct.xilinx.com/bvdocs/publications/ds099-4.pdf
---------------------------------
Steven K. Knapp
Applications Manager, Xilinx Inc.