Answers Database

JTAG/Boundary Scan: Using ATEs to program XC9500 devices


Record #3650

Product Family:  Software

Product Line:  CPLD Implementation

Problem Title:
JTAG/Boundary Scan: Using ATEs to program XC9500 devices


Problem Description:
Keywords: ate, hp, 3070, generad, erase, program, 9500, jtag, boundary, scan, sv
f

Urgency: Standard

General Description: ISP troubleshooting tips while
trying to program XC9500 devices using ATEs.


Solution 1:

1. Work on one device at a time in a boundary scan chain.

   - If any of the following steps fail, use HIGHZ instead of
     BYPASS for untargetted devices.

2. Disable all free running clocks

3. Prepare and execute a set of test vectors to read the IDCODE
from the target device.

4. Prepare and execute a set of test vectors to ERASE the
target device.

5. Prepare and execute a set of test vectors to PROGRAM ***several
addresses*** in the target device.

   - In a multi-part boundary scan chain, initially make certain
     all other devices are blank.
   - If this step fails with all other devices blank, then use
     HIGHZ instead of BYPASS on all non-targetted devices.

6. Prepare and execute a set of test vectors to PROGRAM all
device locations.

   - In a multi-part boundary scan chain, initially make certain
     all other devices are blank.
   - If this step fails with all other devices blank, then use
     HIGHZ instead of BYPASS on all non-targetted devices.

7. Prepare to execute a set of test vectors to READBACK (verify)
all device locations.



Solution 2:

ATE & ISP troubleshooting tips:

1. Use HIGHZ instead of BYPASS on parts not being programmed to
increase system noise immunity.

2. If ERASE is failing, increase ERASE time by 25%

3. If PROGRAM is failing, increase PROGRAM time, 25%

4. If either ERASE or PROGRAM is failing, increase maximum retries
by 2X.



Solution 3:

HP3070 Tips:

**** If you are seeing a duplication of vectors in the VCL file,
you will have to download the latest version of svf2vcl from
the Xilinx
web site at: http://www.xilinx.com/products/hpq.htm ****

1. Add 100 ohm pullup on TCK at TCK probe point on fixture.

2. Add 100 ohm pulldown on TMS at TMS probe point on fixture.

3. Use leads as short as possible on TCK, TMS, TDI and TDO.

4. Define TCK, TMS, TDI and TDO as critical signals.

6. Use 5V drive levels.

7. Add 1nF capacitor in parallel with TCK and TMS resistors.

8. Vary vector cycle times to increase noise immunity.

9. Vary slew rates to increase noise immunity.

10. Use twisted pairs for TAP signal connections for increased
noise immunity.



Solution 4:

Generad GR228X Tips:

1. For fastest ISP execution times and the smallest disk file
sizes, use Deep Serial Memory (DSM) option.

2. Use clock drivers for TCK. or provide an external buffer on
the driver/sensor pin assigned to TCK.



End of Record #3650