beginners/light_control.asm

   1 ;
   2 ; control the light connected to the pwm output pins
   3 ;
   4 ; author: hackbard@hackdaworld.org
   5 ;
   6
   7 ; specify device
   8 .include "../include/2313def.inc"
   9
  10 ; for register/bit definitions compatibility
  11 .include "./s90_to_tiny.inc"
  12
  13 ; ------------------
  14 ; interrupt vectors:
  15 ; ------------------
  16
  17 ; reset
  18 rjmp INIT
  19 ; int0
  20 rjmp INT_ROUTINE
  21 ; int1
  22 reti
  23 ; timer 1 capture
  24 reti
  25 ; timer 1 compare
  26 reti
  27 ; timer 1 overflow
  28 reti
  29 ; timer 0 overflow
  30 reti
  31 ; usart rx complete
  32 rjmp UART_RX
  33 ; usart data register empty
  34 reti
  35 ; usart tx complete
  36 reti
  37 ; analog comperator
  38 reti
  39 ; pin change interrupt
  40 reti
  41 ; timer/counter 1 compare match b
  42 reti
  43 ; timer/counter 0 compare match a
  44 reti
  45 ; timer/counter 0 compare match b
  46 reti
  47 ; usi start condition
  48 reti
  49 ; usi overflow
  50 reti
  51 ; eeprom ready
  52 reti
  53 ; watchdog timer overflow
  54 reti
  55
  56 ; -----
  57 ; code:
  58 ; -----
  59
  60 INIT:
  61         ; set stackpointer
  62         ldi r16,low(RAMEND)     ; write top of ramend (lowbyte)
  63         out SPL,r16             ; to stackpointer
  64
  65         ; rs232 init
  66         ldi r16,0
  67         out UBRRH,r16
  68         ldi r16,12      ; "38.4k bps @ 8 mhz" / "4.8k bps @ 1 mhz"
  69         out UBRRL,r16   ; write to uart baudrate register
  70         ldi r16,(1<<RXEN)|(1<<TXEN)|(1<<RXCIE)  ; enable rx/tx + rx interrupt
  71         out UCSRB,r16   ; write to uart control register
  72
  73         ; int0
  74         ldi r16,(1<<PD2)        ; int0 input
  75         out DDRD,r16
  76         ldi r16,(1<<PD2)        ; int0 pull-up
  77         out PORTD,r16
  78         ldi r16,0               ; interrupt on low level of int0
  79         out MCUCR,r16
  80         ldi r16,(1<<INT0)       ; ir enable
  81         out GIMSK,r16
  82
  83         ; port config
  84         ldi r16,0               ; output
  85         out DDRB,r16
  86         ldi r16,0xff            ; pull high
  87         out PORTB,r16
  88
  89         ; some initial values
  90         ldi r20,0
  91         ldi r17,0xff
  92         ldi r25,0x4c
  93
  94         ; global interrupt enable
  95         sei
  96
  97 MAIN:
  98         out PORTB,r17
  99
 100         rjmp MAIN
 101
 102
 103 UART_RX:
 104         in r29,UDR
 105         UART_OUT:
 106                 sbis UCSRA,UDRE
 107                 rjmp UART_OUT
 108                 out UDR,r29
 109         reti
 110
 111
 112 INT_ROUTINE:
 113         ldi r16,0               ; disable int0
 114         out GIMSK,r16
 115         cpi r17,0xff            ; toggle light
 116         breq TURN_ON
 117         TURN_OFF:
 118                 ldi r17,0xff    ; turn off light
 119                 ldi r25,0x44    ; D
 120                 rjmp CONTINUE
 121         TURN_ON:
 122                 ldi r17,0       ; turn on light
 123                 ldi r25,0x4c    ; L
 124         CONTINUE:
 125                 out PORTB,r17
 126                 sbis UCSRA,UDRE
 127                 rjmp CONTINUE
 128                 out UDR,r25
 129         ldi r20,0
 130         WAIT:
 131                 ldi r21,0
 132                 WAIT_II:
 133                         inc r21
 134                         cpi r21,0xff
 135                         brne WAIT_II
 136                 inc r20
 137                 cpi r20,0xff
 138                 brne WAIT
 139
 140         ldi r16,(1<<INT0) ; (re)activate int0
 141         out GIMSK,r16
 142
 143         reti
 144
 145 ; eof