I assume the official port is used. I wish I could answer all quetions, but some source code owned by MCU vendor, I don’t have the access.
Agree with @aggarg – I am also interested in the definition of those macros,
portSET_INTERRUPT_MASK_FROM_ISR(). And I am also interested in the value of
#define configKERNEL_INTERRUPT_PRIORITY 255
As @aggarg memtioned, configMAX_SYSCALL_INTERRUPT_PRIORITY masks the interrupts which can call FreeRTOS APIs. I am confused, because the ISR priority from my MCU vendor is:
Atomic sections: 3 Radio: 4 LL: 5 USART: 6 Others(default): 7
But configMAX_SYSCALL_INTERRUPT_PRIORITY is 48, which is loaded to basepri before PendSV_Handler calls vTaskSwitchContext. I am confused about 48, which seems cannot mask any ISR. Am I right?
Thanks for asking. Both of them are ulSetInterruptMask(). Then it isn’t the key change that caused this failed sympton.
A value of 48 (0x30) for
configMAX_SYSCALL_INTERRUPT_PRIORITY is reasonable if your MCU uses 3 or 4 bits of interrupt priority. Remember that
configMAX_SYSCALL_INTERRUPT_PRIORITY is shifted, just like BASEPRI.
If your MCU uses 3 interrupt priority bits, then 0x30 corresponds to interrupt priority 1 (because 0x30 >> 5 is 1). This would work correctly given the interrupt priorities you listed.
If your MCU uses 4 interrupt priority bits, then 0x30 corresponds to interrupt priority 3 (because 0x30 >> 4 is 3). This would also work correctly given the interrupt priorities you listed.
Thanks for your education, Jeff. Checked the doc, my MCU uses 3 bits.
well, if you still experience problems, you should publish your entire freertosconfig.h.
Got it! Thanks for great sharing, RAc!