Hands-On RTOS with Microcontrollers

Tips for linking ISRs

When writing ISRs from scratch (as we've done in the previous example), one area that can prove to be a source of unexpected trouble is ensuring your ISR is properly linked in (and executed). That is, even if you've properly set up the peripheral to generate interrupts, your new ISR might never be called because it isn't named properly (instead, the default implementation, defined in a startup file, will likely be called). Here are some tips to make sure that shiny new ISR can be found and properly linked in with the rest of the application:

• STM32 *_IRQHandler function names usually contain the exact peripheral name from the datasheet as a sub-string. For example, USART2 maps to USART2_IRQHandler (notice the "S") and ...