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AR# 1359

JTAG - Pullup and pulldown availability on 5200 TDO

Description

Keywords: xc5200, 5k, bscan, tdo, pullup, pulldown, xde, epic

Urgency: Standard

General Description:
After a 5k device is configured, and if boundary scan is not enabled, then the TDO pin can be used as an output or obuft.

How to access the pullup/pulldown on the TDO pin?

Solution

1

To use the pullup/pulldown in the TDO pin for a output, or obuft, you must draw it in the schematic, or instantiate the pullup/pulldown and TDO pad in the HDL code.

2

Load the .lca file into XDE.

Find out which pad location corresponds to the TDO pin from the
data book depending upon your package.

Run the command 'editblk' on that particular IOB that is the TDO
pin for the given 5k device.

When you execute 'editblk', XDE will let you select either a
pullup, a pulldown, or no pullup/pulldown for the TDO pin, if
bscan is not enabled after the FPGA is configured.

3

Load the .ncd file into EPIC.

Find out which pad location corresponds to the TDO pin from the
data book depending upon your package.

Find the PAD in EPIC using the 'find' command. Use 'Site' as
the criterion. Select the PAD and use Edit->Add to add the PAD
to the database. Select it again and run the 'Editblock'
command.

When you execute 'editblock', EPIC will let you select either a
pullup, a pulldown, or no pullup/pulldown for the TDO pin, if
bscan is not enabled after the FPGA is configured. If the Bscan macro
is in the design, you cannot control this pin.
AR# 1359
Date Created 08/31/2007
Last Updated 09/30/2005
Status Archive
Type ??????