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AR# 7414

2.1i JTAG Programmer - SVF SIR instruction with TDO value comparison has incorrect MASK

Description

Keywords: jtagpgmr, JTAG, programmer, TDO, SVF, mask, INSTRUCTION_CAPTURE

The first SIR instruction in the SVF file generated by JTAG Programmer predicts expected TDO values. These TDO values are the INSTRUCTION_CAPTURE values specified in each device's BSDL file. For some bits, the predicted values are X (don't care), the SVF file improperly specifies that they should be 0.

This will be a problem for Xilinx devices in which the bits marked as X take on a post-configuration value of '1'. The TDO MASK values in SVF files generated by the JTAG Programmer should mask these bits.

解决方案

1

This problem can be identified in the TDO mask value during an SIR instruction.
The capture values on the IR do not mask out don't care's for status bits.
The work-around is to modify the SVF file by hand.
This will be corrected in a future release of the JTAG Programmer software.

Below is an example of how to modify the file to mask out all of the bits.

-------------------------------------------------
1) In SVF file, look for a line that begins with "SIR"

2) In this line, look for "MASK" (not "SMASK")

3) In the "( )" followed by MASK, change all the
values to "0".

4) repeat step 1) for every line that begins with "SIR".

Example:

If you have a line:
SIR TDI SMASK(001) TDO MASK(00FF13)
should be changed to:
SIR TDI SMASK(001) TDO MASK(000000)

If you have a line:
SIR TDI SMASK(001) TDO MASK(F3)
should be changed to:
SIR TDI SMASK(001) TDO MASK(00)

If you have a line:
SIR TDI SMASK(0011)
do not change anything for this line, since there is NO
TDO and MASK( ).

Please note that the number of SIR lines in the file is design dependent.

2

Another way this is identified is that final data shifts have don't care values set to 1 instead of 0 (i.e., the mask is right the data is not).

The current work-around is to modify the SVF file by hand.

This issue will be resolved in a future release of the JTAG Programmer software.
AR# 7414
创建日期 08/31/2007
Last Updated 07/16/2008
状态 Archive
Type 综合文章