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Honored Contributor II


I have potentially detected a Cy_SysTick_GetCountFlag() Issue.

Problem:  Cy_SysTick_GetCountFlag() inconsistently reports a SysTick counter reached 0 count.

Attached is a MTB project highlighting the issue.

Project summary:

  • Targeted for the CY8CPROTO-063-BLE although any PSoC6 board will suffice.
  • Uses retarget-io to the standard debug terminal @ 115.2Kbps.
  • Sets up a SysTick with:
    • CLK_LF as the source (CLK_LF routed to WCO)
    • Reload = (1<<16)-1 =  65535.  This is to have the wrap-around for the SysTick every 2 secs.
    • Callback is Set.
    • Cy_SysTick_GetCountFlag() called in for(;;) loop

The code is very simple.

If the systick_wrap variable is incremented in the Callback ISR, "SysTick counter wrapped!" is printed to the terminal.

If the getcount_flag variable is incremented in the Callback ISR, "GetCount_Flag received!" is printed to the terminal.


The optimum result is that every 2 secs the terminal should have:

SysTick counter wrapped!

GetCount_Flag received!

Actual Observations:

Every 2 secs,  either "SysTick counter wrapped!" OR "GetCount_Flag received!" is printed.

Modified code:

If I comment out lines 133-136 in main.c (disabling the Cy_SysTick_GetCountFlag() call and leaving the Callback enabled)

I get "SysTick counter wrapped!" EVERY 2 secs!

If I comment out line 112 in main.c (disabling the Callback but enabling the Cy_SysTick_GetCountFlag() call)

I get "GetCount_Flag received!" erratically.

I realize some SysTick API calls clear the Count flag as a side-effect.  Once in the for(;;) loop, Only the Callback and the Cy_SysTick_GetCountFlag() is called.


Message was edited by: Len This issue has been reproduced in PSoC Creator as well. Project Attached.

"Engineering is an Art. The Art of Compromise."
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