A warning to all:
If you are using the Stock Kinetis Bootloader v1.2.0 and a Project using the FreeRTOS included with KSDK 2.0 there is a problem with the Systick initialization.
The Kinetis Bootloader uses Systick for its timers. When in the bootloader deinits the Systick it does not clear the SYSTICK_CURRENT_VALUE_REG. When the freertos scheduler starts under certain situations the Systick will not fire untill the SYSTICK_CURRENT_VALUE_REG completely rolls over causing an assert to happen when using tickless idle mode.
If you do not want to change the stock bootloader code you must make a slight change to the vPortSetupTimerInterrupt() initialization in port.c (or define your own because it is weakly defined).
Below is what will always work (Additions in blue):
/* Configure SysTick to interrupt at the requested rate. */
// Clear out the CTRL Register (Just in case it happened to be running)
portNVIC_SYSTICK_CTRL_REG = portNVIC_SYSTICK_CTRL_REG &
~( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT |
portNVIC_SYSTICK_ENABLE_BIT );
// Load the reload value
portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
// Clear out any current values from the bootloader
portNVIC_SYSTICK_CURRENT_VALUE_REG = 0;
// Enable the systick timer
portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT |
portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );
Terry Cooke
