Chapter 3 Introduction to MR308
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3.5.14 Interrupt Management Function

The interrupt management function provides a function to process requested external interrupts in real time.
The interrupt management service calls provided by the MR308 kernel include the following:
Returns from interrupt handler (ret_int)
The ret_int service call activates the scheduler to switch over tasks as necessary when returning from
the interrupt handler.
When using the C language,39, this function is automatically called at completion of the handler func-
tion. In this case, therefore, there is no need to invoke this service call.
Figure 3.43 shows an interrupt processing flow. Processing a series of operations from task selection to register
restoration is called a "scheduler.".
Interrupt
TaskA
Save Registers
Handler Processing
iwup_tsk
ret_int
Task Selection
Restore Registers
TaskB
#
pragma INTHANDLER Declare
(C language)
Figure 3.43 Interrupt process flow
39 In the case that the interruput handler is specified by "#pragma INTHANDLER ".