ledpwm.asm --- drive a blue LED with PWM                     21/04/2006
; Copyright (c) 2006 John Honniball
 
.include "tn2313def.inc"
 ;.include "m8def.inc"

            .org 0x0000
 
; Blue LED on Port B bit 2
            .equ LEDPORT = PortB
            .set LEDBIT =0 ; ##################### equ durch set ersetzt, um die leds durchschalten zu können ###

 
; This program drives a single LED connected to the AVR's I/O port.  It
; is connected so that the cathode of the LED is wired to the AVR pin,
; and the anode of the LED is wired to the 5V power supply via a
; resistor.  The value of that resistor depends on the colour of the LED,
; but is usually a few hundred ohms.
 
; We control the brightness of the LED with Pulse Width Modulation (PWM),
; for two reasons.  Firstly, we have no analog outputs on the AVR chip,
; only digital ones.  Secondly, a LED's brightness  does not respond
; linearly to variations in supply voltage, but it responds much better
; to PWM.
 
; Pulsating LED looks better if it never quite goes "off", but cycles from
; full brightness to a dim state, and back again
            .equ MINBRIGHT = 100
            .equ MAXBRIGHT = 255

; This value controls how fast the LED cycles from bright to dim.  It is
; the number of PWM cycles that we generate for each step in the brightness
; ramp, up and down.  Larger numbers will make the pulsation slower.
            .equ NCYCLES =1
 
   
; Start of program execution after a Reset
            ldi r16,low(RAMEND)                     ; Initialise stack to top of RAM
            out SPL,r16
           ;ldi r16,high(RAMEND)
            ;out SPH,r16
 

; Initialise the hardware
            ldi r16,0b00000111                         ; Set Port B to all outputs
            out DDRB,r16
            
			ldi r16, 0xFF
            out PORTB, r16 

			ldi r16, 0x00 ; ddrd als eingang
            out DDRD, r16 
      
	        ldi r16, 0xFF     ; An allen Pins vom Port D die Pullup-Widerstände
            out PORTD, r16
            nop
           ; ldi r21, 0 ; r19 0

            sbi LEDPORT,LEDBIT               ; Switch off blue LED by setting output pin high

            

; Start with LED at its lowest level, then ramp up to maximum
dopwm:      

ldi r17,MINBRIGHT                       ; R17 holds current brightness level
l1:         ldi r18,NCYCLES                         ; R18 counts PWM cycles, and hence pulsation speed
l2:         cbi LEDPORT,LEDBIT                      ; Output pin low, LED on
            mov r16,r17                             ; R16 controls length of delay (= R17)
            rcall delayn4us                         ; Call delay subroutine
            sbi LEDPORT,LEDBIT                      ; Output pin high, LED off
            ldi r16,255
            sub r16,r17                             ; R16 controls length of delay (= 255 - R17)
            rcall delayn4us                         ; Call delay subroutine
            dec r18                                 ; Decrement PWM cycle counter
            brne l2
            inc r17                                 ; Increase brightness by one step
              



;############################# mein part den ich hinzugefügt habe #############################			  
			  
			sbic PIND, 0 ; ist taster 1 gedrückt dann überspringe rjmp ll9
			rjmp ll9 
			
			inc r21 ; erhöhe r21
            		cpi r21,3 ;vergleiche r21 mit 3
			breq setnew ;ist r21=3 dann springe zu "setnew"
            		rjmp ll8 ; springe zu "ll8"
			setnew:
			ldi r21,0 ; setze den zähler r21 auf 0
            
			ll8:
            		cpi r21,0 ; vergleiche r21 mit 0 
            		brne led2 ; wenn r21 nicht 0 ist dann springe zu led2
			.set LEDBIT =0  ;das ledbit setzen
			rjmp ll9 ; zum ende des codeblocks springen

			led2:
			cpi r21,1 ;vergleiche r21 mit 1 
            		brne led3 ;wenn r21 nicht 1 ist dann springe zu led2
			.set LEDBIT =1  ;das ledbit setzen
			rjmp ll9 ;zum ende des codeblocks springen
			
			led3:
			cpi r21,2 ;vergleiche r21 mit 2
            		brne ll9 ;wenn r21 nicht 2 ist dann springe zum ende des codeblocks
		    	.set LEDBIT =2 ;das ledbit setzen
			

            		ll9:
			  
;############################# mein part den ich hinzugefügt habe ende #############################				  
brne l1
 
; Now ramp back down to the minimum brightness
            ldi r17,MAXBRIGHT                       ; R17 holds current brightness level
l3:         ldi r18,NCYCLES                         ; R18 counts PWM cycles, and hence pulsation speed
l4:         cbi LEDPORT,LEDBIT                      ; Output pin low, LED on
            mov r16,r17                             ; R16 controls length of delay (= R17)
            rcall delayn4us                         ; Call delay subroutine
            sbi LEDPORT,LEDBIT                      ; Output pin high, LED off
            ldi r16,255
            sub r16,r17                             ; R16 controls length of delay (= 255 - R17)
            rcall delayn4us                         ; Call delay subroutine
            dec r18                                 ; Decrement PWM cycle counter
            brne l4
            dec r17                                 ; Decrease brightness by one step
            cpi r17,MINBRIGHT                       ; Have we reached the minimum?
            brne l3
 
            rjmp dopwm                              ; Loop back to start
 
; DELAYN4US
; Delay for (R16 * 4) microseconds
delayn4us:  tst r16                                 ; R16 = 0? (no delay)
            breq dly4
dly2:       ldi r24,low(16)
            ldi r25,high(16)
dly3:       sbiw r24,1                              ; 2 cycles
            brne dly3                               ; 2 cycles
            dec r16
            brne dly2
dly4:       ret                                     ; Return to caller