Question

State how to enable an interrupt by a NVIC function. What is the difference between the following two statements?

NVIC->ISER[1] |= (1<<6); //enableIRQ(USART2_IRQn)

NVIC_EnableIRQ  ( 38 );   // 38: USART2 interrupt no

Find out the NVIC functions for the following operation

Resets the whole system including peripherals.

Sets the priority grouping.

Returns the value of the current priority grouping.

Enables the interrupt IRQn.

Disables the interrupt IRQn.

Sets the priority for the interrupt IRQn.

Returns the priority for the specified interrupt.

Sets the interrupt IRQn pending.

Returns the pending status of the interrupt IRQn.

Clears the pending status of the interrupt IRQn, if it is not already running or active.

Returns the active status for the interrupt IRQn.

Answer 1

Solution:

Note: multiple questions asked, please post unanswered questions separately

State how to enable an interrupt by a NVIC function.

• The Nested Vector Interrupt Controller (NVIC) is a controller used to perform different functions associated with interrupts.
• “void NVIC_EnableIRQ (IRQn_Type IRQn           )” function evoke is used to enable an interrupt the device specific interrupt value IRQn is used to identify the device from which interrupt is happened.
• The SETENA register will control the enable interrupt process.

What is the difference between the following two statements?

NVIC->ISER[1] |= (1<<6); //enableIRQ(USART2_IRQn)

NVIC_EnableIRQ  ( 38 );   // 38: USART2 interrupt no

• The first statement is to enable the interrupts from the interrupt service routine by selecting the interrupt priority.
• The interrupt values received at the USART port will be used here.
• The second statement is used to enable a particular interrupt by specifying that interrupt number.