Added CStack check to project by putting it into the device object as property 512. The compile shows 648 bytes of RAM used, and the device has 1024 bytes of RAM, leaving 376 for the CStack. Property 512 index 0 returns 376. So, my understanding is that the RAM that is not allocated to the variables is used for the CStack, something to keep in mind when developing. After some exercising, the stack shows 159 CStack bytes free, meaning that 216 bytes of CStack are used. Note that 0xC5 (197) was used to paint the CStack.

bacnet-stack/ports/atmega168/main.c

@@ -139,7 +139,6 @@ static void input_switch_read(
 }
 
 /* stack checking */
-#if STACK_CHECK_ENABLED
 #if defined(__GNUC__)
 extern uint8_t _end;
 extern uint8_t __stack;
@@ -171,28 +170,6 @@ void StackPaint(void)
                     "    breq .loop"::);
 #endif
 }
-
-static uint16_t StackCount(void)
-{
-    const uint8_t *p = &_end;
-    uint16_t       c = 0;
-
-    while(*p == STACK_CANARY && p <= &__stack)
-    {
-        p++;
-        c++;
-    }
-
-    return c;
-}
-
-static void Analog_Value_Task(void)
-{
-    extern float AV_Present_Value[MAX_ANALOG_VALUES];
-    
-    AV_Present_Value[0] = (float)StackCount();
-}
-#endif
 #endif
 
 static uint8_t PDUBuffer[MAX_MPDU];
@@ -216,9 +193,6 @@ int main(
         /* BACnet handling */
         pdu_len = datalink_receive(&src, &PDUBuffer[0], sizeof(PDUBuffer), 0);
         if (pdu_len) {
-#if STACK_CHECK_ENABLED
-            Analog_Value_Task();
-#endif
             LED_NPDU_ON();
             npdu_handler(&src, &PDUBuffer[0], pdu_len);
             LED_NPDU_OFF();