8 Replies Latest reply on Jan 22, 2016 6:38 AM by user_478787221

    Trying to understand clocks

    user_478787221

      I made a very simple test jig , where the system clock is set to 48MHz, no dividers.  I am simply toggling a pin.

         

      int main()
      {
          /* Place your initialization/startup code here (e.g. MyInst_Start()) */

         

          /* CyGlobalIntEnable; */ /* Uncomment this line to enable global interrupts. */
          for(;;)
          {
              SCLK_Write(0x01);
              SCLK_Write(0x00);
              /* Place your application code here. */
          }
      }

         

      but I am not seeing the pin toggle at nearly the rate I would expect given the system clock speed.  Frequency of the output is 350kHz, so it is 48MHz/350kHz = 137 off from 48MHz.  I have a hard time believing that there are so many cycles per instruction.   Rather, I am thinking something is not configured quite right in my project.  What could it be?

         

      Also, why is there a question mark under Desired for Sysclk?