Hands-On RTOS with Microcontrollers

USART2_IRQHandler

This ISR is also slightly more involved since it is required to keep track of the position in a queue:

1. Private globals are used by USART2_IRQHandler because they need to be accessible by both the ISR and used by both USART2_IRQHandler  and startReceiveInt:

static bool rxInProgress = false;static uint_fast16_t rxLen = 0;static uint8_t* rxBuff = NULL;static uint_fast16_t rxItr = 0;

2. The same paradigm for storing xHigherPriorityTaskWoken and SEGGER SystemView tracing is used in this ISR, just like in the last example:

void USART2_IRQHandler( void ){     portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;     SEGGER_SYSVIEW_RecordEnterISR();

3. Next, errors are checked by reading the overrun (ORE), noise error (NE), framing error (