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AR# 29880

MIG v2.0 - Is it required with the ISE 9.2i design tools to manually set the drive strength for the Spartan-3A/-3A DSP DDR and DDR2 MIG designs?

Description

The Spartan-3A and Spartan-3A DSP UCFs output from MIG 2.0 include the following comment:

############################################################

## There is an issue with ISE 9.1 tool, default drive strength of LVCMOS18

for Spartan-3A

## should set to 8MA, the tool is setting it to 12MA.

## We are setting the drive strength to 8MA in UCF file for following

signal/signals

## as work around until the ISE bug is fixed

#############################################################

Does this issue still exist in the ISE 9.2i design tools?

Solution

This issue still exists with the ISE 9.2i design tools. The drive strength must be set to 8 mA ('DRIVE = 8') within the UCF when using ISE 9.2i.

The drive strength is set to 8 mA for the following signals:

- reset_in_n

- cntrl0_led_error_output1

- cntrl0_data_valid_out

- cntrl0_init_done

The drive strength for reset_in_n was added for completeness and will not have any effect on the final design, as this is an input signal.

This issue is fixed in ISE 10.1.

AR# 29880
Date Created 12/04/2007
Last Updated 12/15/2012
Status Active
Type General Article