;
; hello.light.44.asm
; turns on and off leds relative to light levels
; jonathan ward
;


.include "tn44def.inc"
;
; definitions
;

;.equ tx_pin = PB2; transmit pin

.equ led1 = PA1; led pin
.equ led2 = PA2; led pin
.equ led3 = PA6; led pin
.equ led4 = PA7; led pin

.equ low_level = 1000 
.equ lowmid_level = 750  
.equ mid_level = 500 
.equ high_level = 250 

;
; registers
;
.def bit_count = R16; bit counter
.def temp = R17; temporary storage
.def temp1 = R18; temporary storage
.def txbyte = R19; data byte

.def ad_high = R20; data byte
.def mid = R21; data byte
;
; code segment
;
.cseg
.org 0
rjmp reset




delay:
ldi temp, 1
delay_loop:
   ldi temp1, 150
   delay_loop1:
      dec temp1
      brne delay_loop1
   dec temp
   brne delay_loop
   ret
;
; main program
;
reset:
   ;
   ; set stack pointer to top of RAM
   ;
   ldi temp, high(RAMEND)
   out SPH, temp
   ldi temp, low(RAMEND)
   out SPL, temp
   ;

	;init led
	cbi PORTA, led1
	sbi DDRA, led1

	cbi PORTA, led2
	sbi DDRA, led2

	cbi PORTA, led3
	sbi DDRA, led3

	cbi PORTA, led4
	sbi DDRA, led4


   ;
   ; init A/D
   ;
   ; use Vcc as reference

   cbi ADMUX, REFS1 ; 
   cbi ADMUX, REFS0 ; 

   cbi ADMUX, ADLAR ; right-adjust result

   cbi ADMUX, MUX5 ; set MUX to ADC0 (PA0)
   cbi ADMUX, MUX4 ; "
   cbi ADMUX, MUX3 ; "
   cbi ADMUX, MUX2 ; "
   cbi ADMUX, MUX1 ; "
   cbi ADMUX, MUX0 ; "
   
   sbi ADCSRA, ADEN ; enable A/D
   cbi ADCSRA, ADPS2 ; set prescaler to /2
   cbi ADCSRA, ADPS1 ; "
   cbi ADCSRA, ADPS0 ; "

   ;
   ; start main loop
   ;
   main_loop:

	rcall four_leds_off

      sbi ADCSRA, ADSC ; start conversion
      AD_loop:
         sbic ADCSRA, ADSC ; loop until complete
	 rjmp AD_loop

	;rcall leds_on
        ;rcall leds_off
	rcall light

      rjmp main_loop


light:

;turn on leds on relative to light levels

in ad_high, ADCL
in ad_high, ADCH
ldi temp, high(low_level)
cpc temp, ad_high
brlo main_loop
rcall one_led_on

ldi temp, high(lowmid_level)
cpc temp, ad_high
brlo main_loop
rcall two_leds_on

ldi temp, high(mid_level)
cpc temp, ad_high
brlo main_loop
rcall three_leds_on

ldi temp, high(high_level)
cpc temp, ad_high
brlo main_loop
rcall four_leds_on

ret










one_led_on:
sbi PORTA, led1
rcall delay
ret

one_led_off:
cbi PORTA, led1
ret

two_leds_on:
sbi PORTA, led1
sbi PORTA, led2
rcall delay
ret

two_leds_off:
cbi PORTA, led1
cbi PORTA, led2
ret

three_leds_on:
sbi PORTA, led1
sbi PORTA, led2
sbi PORTA, led3
rcall delay
ret

three_leds_off:
cbi PORTA, led1
cbi PORTA, led2
cbi PORTA, led3
ret

four_leds_on:
sbi PORTA, led1
sbi PORTA, led2
sbi PORTA, led3
sbi PORTA, led4
rcall delay
ret

four_leds_off:
cbi PORTA, led1
cbi PORTA, led2
cbi PORTA, led3
cbi PORTA, led4
ret