The Definitive Guide to the ARM Cortex-M3

CHAPTER 9 Interrupt Behavior

In This Chapter:

• Interrupt/Exception Sequences

• Exception Exits

• Nested Interrupts

• Tail-Chaining Interrupts

• Late Arrivals

• More on the Exception Return Value

• Interrupt Latency

• Faults Related to Interrupts

Interrupt/Exception Sequences

When an exception takes place, a number of things happen:

• Stacking (pushing eight registers’ contents to stack)
• Vector fetch (reading the exception handler starting address from the vector table)
• Update of the stack pointer, link register, and program counter

Stacking

When an exception takes place, the registers PC, PSR, R0–R3, R12, and LR are pushed to the stack. If the code that is running uses the PSP, the process stack will be used; if the code that is running ...