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Newbie pagews2
Newbie
121 Views
Registered: ‎01-11-2019

FPGA Lockup after configuration

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I have a problem I haven't been able to sort out.

I purchased a demo board which included a XC3S250E and a XCF02S. I am using
ISE and IMPACT with a JTAG programmer to program the board and the
demo board works fine with my application. The schematic of the demo board
was available so I designed a custom board for my application based on
the demo board with the addition of the extra components needed to support
my application. I compared the schematic with a mode 0 configuration of
the FPGA in the manuals and the circuit seems consistent. I am not using any of the
pins that show as being involved in either the JTAG or XCF02S
initialization of the FPGA.

When I install my application on my custom
board, IMPACT correctly identifies the components. I can program and verify
the XCF02S and program the XC3S250E. When the FPGA is programmed directly
with the JTAG, my application runs correctly. However, when I attempt to
initialize the FPGA from the PROM it runs through the programming cycle
but at the end all the FPGA ports sink current and the application does
not run. (There are LEDs on a number of the ports so I know that the ports
are sinking current.) This happens on both a power on reset or a stimulus
on the prog pin. I have verified that all the signals between the
FPGA and the PROM have signals on them that appear to be correct. I
checked the status of the FPGA after a failed configuration and I don't
see any errors.

What would cause the FPGA to lock up with all ports sinking at the end
of a programming cycle? Is there any information that I could supply
that would help diagnose the problem.

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1 Solution

Accepted Solutions
Newbie pagews2
Newbie
62 Views
Registered: ‎01-11-2019

回复: FPGA Lockup after configuration

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Thank you for your response.  It pointed me in the right direction to determine the solution.

When I created the simple application (blink one LED)  and loaded it into the board, I found that it worked.  So, my hardware is correct.  I started experimenting with the failing application.  I found that the problem was due to my lack of understanding of IMPACT.  During the development of my application, each time I would configure the FPGA through IMPACT, IMPACT would note that the program had changed and ask to load the latest version.  What I did not understand was that IMPACT only changed the code being loaded into the FPGA, but NOT the image that was to be loaded into the PROM.  So the PROM was being reprogrammed with an early failing version of the code, not the latest working code.  I found that I had to chase through some other menu options to get the PROM code updated.  When I did that, the system worked fine.

My explanation might not be completely accurate but the final effect is that I'm able to get things working now.

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2 Replies
Xilinx Employee
Xilinx Employee
89 Views
Registered: ‎08-10-2008

回复: FPGA Lockup after configuration

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1. I
checked the status of the FPGA after a failed configuration and I don't
see any errors.

How can you tell this? Please specify and show me the status register after the failure.

2. Test with a very simple design: enable only one port of FPGA and this port is to lit a LED on the board by assign xxx=1. What can you see with this design loaded from PROM?

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Newbie pagews2
Newbie
63 Views
Registered: ‎01-11-2019

回复: FPGA Lockup after configuration

Jump to solution

Thank you for your response.  It pointed me in the right direction to determine the solution.

When I created the simple application (blink one LED)  and loaded it into the board, I found that it worked.  So, my hardware is correct.  I started experimenting with the failing application.  I found that the problem was due to my lack of understanding of IMPACT.  During the development of my application, each time I would configure the FPGA through IMPACT, IMPACT would note that the program had changed and ask to load the latest version.  What I did not understand was that IMPACT only changed the code being loaded into the FPGA, but NOT the image that was to be loaded into the PROM.  So the PROM was being reprogrammed with an early failing version of the code, not the latest working code.  I found that I had to chase through some other menu options to get the PROM code updated.  When I did that, the system worked fine.

My explanation might not be completely accurate but the final effect is that I'm able to get things working now.

0 Kudos