FreeRTOS - Interrupt Management
What is wrong with this usage?#define configMAX_SYSCALL_INTERRUPT_PRIORITY (0x80)
On a Cortex-M with 4 priority bits.
What is wrong with this usage?
medium📝 Debug Q7 of 15
Step-by-Step Solution
Solution:
Step 1: Calculate max priority value for 4 bits
Max priority number is 2^4 - 1 = 15, shifted left by (8 - 4) = 4 bits gives max 15 << 4 = 0xF0.Step 2: Compare given value
0x80 is 128 decimal, which corresponds to priority 8 shifted left 4 bits (8 << 4 = 128), so it is shifted correctly.Step 3: Check if 0x80 exceeds max allowed
0x80 is less than max 0xF0, so it does not exceed maximum allowed.Final Answer:
No error, this is valid -> Option DQuick Check:
Priority must be shifted left by (8 - priority bits) [OK]
Quick Trick: Max priority = (2^bits -1) << (8 - bits) [OK]
Common Mistakes:
- Ignoring max priority range
- Not shifting priority
- Assuming any hex is valid
Master "Interrupt Management" in FreeRTOS
Want More Practice?
15+ quiz questions · All difficulty levels · Free
Free Signup - Practice All QuestionsMore FreeRTOS Quizzes