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Registered: ‎04-21-2017

Zynq Processor hangs on PL access

I have two identical PCBAs in which one of the Zynq SoCs work as expected, and the other does not.


Here is what I am seeing:

  • On the working unit, I can run via JTAG or load my (FSBL + BIT + ELF) from QSPI just fine.
  • On the defunt unit.:
    • I can program to the QPSI, with the exact same mcs file.
    • From QPSI, the FSBL loads and the bitstream loads just fine. The FSBL debug info leads me to believe that the application ELF is loaded and handed off as well, but it never runs.
    • From JTAG, I can load in a hello world + bitstream and it runs fine.
    • From JTAG, if I load any application that tries to access AXI peripherals in the PL ( ex AXI GPIO). The processor gets in to a state that I cannot halt. I get this error:
      • “Cannot halt processor core, timeout”



Other notes:

  • No external PL clocks. PL is driven by PS FCLK0.
  • Zynq XC7Z015-2CLG485I
  • Bare metal applications
  • No Trust Zone enabled
  • DDR tests run fine
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2 Replies
Registered: ‎06-19-2015

Re: Zynq Processor hangs on PL access

Hi @ashton.johnson


Have you verified all clock sources and voltage are same in both boards? Any terminations resisters missing for PL clocks?

For PL, drive the clock from PS instead of from board.




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Registered: ‎04-21-2017

Re: Zynq Processor hangs on PL access

Hi, Thanks for the reply. 


I had the IC replaced and the PCBA is operating nominally now.


Forever unresolved....

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