C program to count numbers and display using LEDS

Introduction: In this lab exercise the c program has been compiled and examined the execution of interrupt service routine.

Technical Discussion Interrupts: An interrupt is a signal generated by the software or hardware which indicates an event that requires an attention by the processor. To service an interrupt, interrupt service routine (IS! is called. Interrupt Service Routine (ISR):

An interrupt service routine is a routine that invo"es the hardware in response to an interrupt occurred by an event. IS handles the interrupt and returns the status to the processor. Answers: 1) Regis ter # $  ' 4  /

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") The return address is same after servicing the interrupt. The return address is 0x080007F1. The address before servicing interrupt is 0x0800007F1

The address after servicing interrupt is 0x0800007F1, which is same.

2) So#tware $ro%ect  The ) program is developed using "eil compiler. Interrupt service routines has been used as per the requirements provided. 6irst all the leds are o7, then blue led switched on after random amount of time. Then the program chec"s for push button continuously and also increments the counter value. If the button is pressed the IS gets activates and the 8ag 9isr&status: is updated in the interrupt service routine. After that the count value is displayed using  leds for 4ms. The following is the 8owchart.

'lowchart:

Results:

Conclusion

 The ) program is compiled and analy;ed the execution of an interrupt. I am able to understand how an interrupt wor"s in real time applications.

Appendi: ode:
=platform.h> =gpio.h> =stdlib.h> ?leds.h? ?delay.h?

static int count @ # int pdbgIS @ # int redBon @ $ int pdbgAI2, pSC int Daddress @ (intD!#x'###$### EE 8ag indicating IS implemetation static int isrBstatus@# int randomTime void buttonBpressBisr(int sources! F pSC @ $ gpioBset(&BGHBIS, $! pdbgIS @ $ gpioBset(&BGHBIS, #! pdbgIS @ # pSC @ gpioBget(&BSC! isrBstatus@$ J int main(void! F EE initialising peripherals ledsBinit(! gpioBsetBmode(&BGHBIS, 1utput! gpioBsetBmode(&BGHBAI2, 1utput! EE Set up onKboard switch. gpioBsetBtrigger(&BSC, ising! gpioBsetBcallbac"(&BSC, buttonBpressBisr! pSC @ gpioBget(&BSC!  BBenableBirq(! while ($! F EETurning o7 3eds ledsBset(#, #, #! EEclearing the counter

count@# EE resetting the 8ag isrBstatus@# EE delay for random time randomTime@(rand(!L$#! delayBms(randomTimeD#! EE Turn on one 3*G K blue ledsBset(#,#,$! while(isrBstatus@@#!F gpioBtoggle(&BGHBAI2! pdbgAI2 @ gpioBget(&BGHBAI2! pSC @ gpioBget(&BSC! countMM J ledsBset(count N $, count N -, count N '! EEsaving to memory Daddress@count delayBms(4###! J J