title: Stack overflows after giving semaphore from ISR in FreeRTOS
body: <p>I'm trying to use FreeRTOS's <code>xSemaphoreGiveFromISR</code> function and the accompanying <code>portEND_SWITCHING_ISR</code> macro to give a semaphore from within an interrupt that handles the end of an I2C transaction.</p>
  
  <p>Every time I do, I end up in my program's application stack overflow hook function. The only change from a working version has been adding this line to the ISR, and I've doubled the size of the stack from <code>8192</code> to <code>16384</code> which didn't help.</p>
  
  <p>Does anyone have thoughts about what gotcha is getting me?</p>
  
  <p>My <code>configCHECK_FOR_STACK_OVERFLOW</code> value is 1.</p>