/*
* See header file for description.
*/
portBASE_TYPE xPortStartScheduler( void )
{
/* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See
http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
configASSERT( ( configMAX_SYSCALL_INTERRUPT_PRIORITY ) );
/* Make PendSV and SysTick the same priority as the kernel. */
*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI;
*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI;
/* Configure the regions in the MPU that are common to all tasks. */
prvSetupMPU();
/* Start the timer that generates the tick ISR. Interrupts are disabled
here already. */
prvSetupTimerInterrupt();
/* Initialise the critical nesting count ready for the first task. */
uxCriticalNesting = 0;
/* Start the first task. */
__asm volatile( " svc %0 \n"
:: "i" (portSVC_START_SCHEDULER) );
/* Should not get here! */
return 0;
}
/*
* See header file for description.
*/
portBASE_TYPE xPortStartScheduler( void )
{
/* Make PendSV and SysTick the same priroity as the kernel. */
*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI;
*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI;
/* Configure the regions in the MPU that are common to all tasks. */
prvSetupMPU();
/* Start the timer that generates the tick ISR. Interrupts are disabled
here already. */
prvSetupTimerInterrupt();
/* Initialise the critical nesting count ready for the first task. */
uxCriticalNesting = 0;
/* Start the first task. */
__asm volatile( " svc %0 \n"
:: "i" (portSVC_START_SCHEDULER) );
/* Should not get here! */
return 0;
}
/*
* See header file for description.
*/
BaseType_t xPortStartScheduler( void )
{
/* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. See
http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
configASSERT( ( configMAX_SYSCALL_INTERRUPT_PRIORITY ) );
#if( configASSERT_DEFINED == 1 )
{
volatile uint32_t ulOriginalPriority;
volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
volatile uint8_t ucMaxPriorityValue;
/* Determine the maximum priority from which ISR safe FreeRTOS API
functions can be called. ISR safe functions are those that end in
"FromISR". FreeRTOS maintains separate thread and ISR API functions to
ensure interrupt entry is as fast and simple as possible.
Save the interrupt priority value that is about to be clobbered. */
ulOriginalPriority = *pucFirstUserPriorityRegister;
/* Determine the number of priority bits available. First write to all
possible bits. */
*pucFirstUserPriorityRegister = portMAX_8_BIT_VALUE;
/* Read the value back to see how many bits stuck. */
ucMaxPriorityValue = *pucFirstUserPriorityRegister;
/* Use the same mask on the maximum system call priority. */
ucMaxSysCallPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY & ucMaxPriorityValue;
/* Calculate the maximum acceptable priority group value for the number
of bits read back. */
ulMaxPRIGROUPValue = portMAX_PRIGROUP_BITS;
while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
{
ulMaxPRIGROUPValue--;
ucMaxPriorityValue <<= ( uint8_t ) 0x01;
}
/* Shift the priority group value back to its position within the AIRCR
register. */
ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
/* Restore the clobbered interrupt priority register to its original
value. */
*pucFirstUserPriorityRegister = ulOriginalPriority;
}
#endif /* conifgASSERT_DEFINED */
/* Make PendSV and SysTick the same priority as the kernel, and the SVC
handler higher priority so it can be used to exit a critical section (where
lower priorities are masked). */
portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI;
portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI;
/* Configure the regions in the MPU that are common to all tasks. */
prvSetupMPU();
/* Start the timer that generates the tick ISR. Interrupts are disabled
here already. */
vPortSetupTimerInterrupt();
/* Initialise the critical nesting count ready for the first task. */
uxCriticalNesting = 0;
/* Ensure the VFP is enabled - it should be anyway. */
vPortEnableVFP();
/* Lazy save always. */
*( portFPCCR ) |= portASPEN_AND_LSPEN_BITS;
/* Start the first task. */
prvStartFirstTask();
/* Should not get here! */
return 0;
}
