Number of clock cycles in the execution of "SysCtlDelay" in the simulator.

CharlesA. said:

In the SysCtlDelay documentation

Give a link - so that people can see exactly what you're looking at, and in context.

CharlesA. said:

In simulator, it takes 4 cycles / loop

How, exactly, do you determine that?

I am working with the Keil MDK-Lite version 5.24.2 uVision toolchain, I am working with a Stellaris® LM4F120 LaunchPad Evaluation Board from Texas Instruments. The microcontroller is tm4c123gh6pm.
The software used is an example (Project0) supplied by Texas in Stellarisware and it is:

int
main(void)
{
    //
    // Setup the system clock to run at 50 Mhz from PLL with crystal reference
    //
  SysCtlClockSet(SYSCTL_SYSDIV_2_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);

    //
    // Enable and configure the GPIO port for the LED operation.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED);

    //
    // Loop Forever
    //
    while(1)
    {
        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, RED_LED);
AL = 1;
        //
        // Delay for a bit
        //
        SysCtlDelay(2000000);

        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, BLUE_LED);
AL = 0;
        //
        // Delay for a bit
        //
        SysCtlDelay(2000000);
    }
}

The execution of each Delay in the simulator occupies a time of 8000000 states. Executing the Delay loop step by step, it is also observed that each loop occupies 4 states.

Stellarisware? That's a blast from the past!

CharlesA. said:

The software used is an example (Project0) supplied by Texas in Stellarisware

So have you asked Texas Instruments about this?

We are also using Tiva and Tivaware, but now I cannot have it.
However, I suppose it presents the same problem

int
main(void)
{
    //
    // Setup the system clock to run at 50 Mhz from PLL with crystal reference
    //
  SysCtlClockSet(SYSCTL_SYSDIV_2_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);

    //
    // Enable and configure the GPIO port for the LED operation.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED);

    //
    // Loop Forever
    //
    while(1)
    {
        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, RED_LED);
AL = 1;
        //
        // Delay for a bit
        //
        SysCtlDelay(2000000);

        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, BLUE_LED);
AL = 0;
        //
        // Delay for a bit
        //
        SysCtlDelay(2000000);
    }
}

Again, that's TI's software - so you should be asking them about it, and/or  for clarifications on their documentation!

By measuring the switching time of the port with an oscilloscope, it is confirmed that Delay actually occupies 3 cycles / loop.
And in the simulation 4 cycles / loop.