How can I identify IRQ handlers that occur during a normal CPU execution?

Question

I have a time-sensitive block of code run purely by the CPU, not within any interrupt handler or peripheral. Part of the execution is getting interrupted, and so what I would like is to simply identify which IRQ or IRQs are occurring, preferably in real time. To be clear, I am not looking for advice regarding superior techniques for time-sensitive operations, I would just like to identify which IRQ or IRQs are occurring in a particular block of code. Is there a way to do this in general, or is it a process of narrowing down the potential suspects. Detailed answers much appreciated. I am using Segger Embedded Studio in my development. Thank you!

havingnordicfun · Accepted Answer

I wanted to reply with what I ended up doing to accomplish the aim of my original question: One can access the vector table with SCB and remap to a location in RAM, assign every entry in the vector table to a function that forwards IRQs and intercepts them there: #include "core_cm4.h" #define VECTOR_TABLE_SIZE 256 /**< Size of the vector table in bytes. (16 Cortex + 42 Nordic = 58 words. Next power of 2 = 256) */ static uint32_t vector_table_ram_trampoline[VECTOR_TABLE_SIZE] __attribute__ ((aligned (128))); static uint32_t vector_table_ram[VECTOR_TABLE_SIZE] __attribute__ ((aligned (128))); typedef void (*irq_handler_t)(void); void irq_forwarder(void){ uint32_t ipsr = __get_IPSR(); uint8_t isr = ipsr & 0xFF; // this is the IRQ number that is occurring irq_handler_t irq_handler = (irq_handler_t)(vector_table_ram[isr]); irq_handler(); } /* * Copy the interrupt vector table into RAM and set VTOR to point to it. * Call before anything else in main */ void vector_table_init() { memcpy(vector_table_ram_trampoline, (uint32_t *) (SCB->VTOR), VECTOR_TABLE_SIZE); memcpy(vector_table_ram, (uint32_t *) (SCB->VTOR), VECTOR_TABLE_SIZE); __disable_irq(); SCB->VTOR = (uint32_t)&vector_table_ram_trampoline; // Set VTOR to point to new vector table for(int i=0; i

How can I identify IRQ handlers that occur during a normal CPU execution?

Top Replies