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Altera_Forum
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13 years ago

Hardware Interrupt

Hello everyone, i have a simple question but i am a beginner and after searching the web for a day an reading nearly all nios documentations i decided to use a Forum. I hope someone can help me. ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

i have a code example.

it nearly works, It jumps in the IRS but dont know wicht key were pushed dont know why :-/ 


	.equ STACK_SIZE, 0x400#  stack size
	.equ PUSHBUTTON_BASE, 0x10000050
	.data
TST_PAK1:
	.word 0x11112222#  test data
STACK_END:
	.word 0xFFFFFFFF#  end of stack
	.skip STACK_SIZE#  stack area filled with 0
# #############################################
# 	Exception# #
# 		# #
# #############################################	
	.section .exceptions, "ax"	#  Fixierung der Routine
	subi 		sp, sp, 4	#  Stacksicherung
	stw		r13, (sp)
 	subi		sp, sp, 4
 	stw		r4, (sp)
 	subi		sp, sp, 4
 	stw		r3, (sp)
 	
ISR:
	movia 		r5, 0x810
	rdctl 		et, ctl4 	#  Überprüfung auf Interrupt 
	beq 		et, r0, SKIP	 #  Interrupt ist weg, raus aus der Exception
	subi 		ea, ea, 4 	#  PC Anpassung
	andi 		r13, et, 0b1000
	bne		r13, r0, IRQ1_ISR#  Test ob es IRQ1 aktiv ist
	
	andi 		r13, et, 0b0010
	bne		r13, r0, IRQ3_ISR#  Test ob es IRQ3 aktiv ist 
	
	br		SKIP					
IRQ1_ISR:				#  Erste Taste gedrückt
	movia		r4, 15
	stw		r4, (r5)
	br 		SKIP					
IRQ3_ISR:				#  Vierte Taste gedrückt
	
	stw		r0, (r5)
	movia 		r3, 15
										
SKIP:					#  Springt zum Ende der interrupt-service routine
	ldw		r3, (sp)
	addi		sp, sp, 4
	ldw		r4,(sp)
	addi		sp, sp, 4
	ldw		r13, (sp)
	addi		sp, sp, 4
	eret 				#  Raus aus der Exception
# ##############################################
# 	End Exception	# 
# 			# 
# ##############################################
# ##############################################
#  TEXT SECTION
#  Executable code follows
# ##############################################
	.global _start
	.text
_start:
	
	movia	sp, STACK_END	#  load data section's start address
	addi	sp, sp, STACK_SIZE	       #  stack start position should
					               #  begin at end of section
	
	subi 	sp, sp, 4		
	stw 	r15, (sp)
	subi 	sp, sp, 4
	stw 	r16, (sp)
	
	movi		r16, 0x10#  Interrupt starten
	movi		r15, 1
	wrctl		ctl3, r16
	wrctl		ctl0, r15
				#  Taster Interrupts aktivieren
	movia	r16, 0x0840
	movi		r15, 0x9#  Maske für die Interrupts 1001 => 0x9
	stw		r15, 8(r16)#  Maske in der Adresse von Tastern reinschreiben um Interrupts aktivieren
	
	ldw 	r16, (sp)	#  Stack 
	addi 	sp, sp, 4
	ldw 	r15, (sp)
	addi 	sp, sp, 4
	
	br 		endloop
endloop:
	br endloop	#  that's it
.end