Hardware Interrupt

Altera_Forum · ‎07-01-2012

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.

Can someone tell me how to initialise a hardware interrupt in assembler? I Tried many things with no result and i just want to programm a counter which counts +1 evry time i press key0 and reset when i press key3 with an interrupt bur nothing works.

(Cyclone II)

hope someone can help me and sry for the bad english

Altera_Forum · ‎07-04-2012

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

Altera_Forum · ‎07-06-2012

Typically with keyboard interrupts you read some registers of the keyboard to figure out which key was pressed. If you are not doing that then you would need to add that to your ISR.

This might be easier if you wrote your code in C.... just saying :)