beginners/test_ports_uart.asm

   1 ;
   2 ; test all ports and uart
   3 ;
   4
   5 .include "../include/m32def.inc"
   6
   7 INIT:
   8
   9         ; all ports outputs
  10         ldi r16,0xff
  11         out DDRA,r16
  12         out DDRB,r16
  13         out DDRC,r16
  14         out DDRD,r16
  15
  16         ; uart baudrate (8mhz -> 38.4k) + enable
  17         ldi r16,0
  18         out UBRRH,r16
  19         ldi r16,12
  20         out UBRRL,r16
  21         sbi UCSRB,TXEN
  22
  23         ; led counter
  24         ldi r17,0
  25         ; loop counter
  26         ldi r18,0
  27
  28 MAINLOOP:
  29
  30         ; reset loop counter
  31         ldi r18,0
  32
  33         ; the delay loop
  34         LOOP:
  35
  36                 ; the dely loop in the delay loop
  37                 ldi r22,0
  38                 INNERLOOP:
  39
  40                         inc r22
  41                         cpi r22,0xff
  42                         brne INNERLOOP
  43
  44                 ; increase loop counter
  45                 inc r18
  46
  47                 ; check loop counter
  48                 cpi r18,0xff
  49
  50                 ; continue if loop counter = 0xff
  51                 ; else do loop again
  52                 brne LOOP
  53
  54         ; shift the led counter
  55         lsl r17
  56
  57         ; set first bit if led counter is equal zero
  58         cpi r17,0
  59         brne LEDOUT
  60         ldi r17,1
  61
  62         ; drive the leds
  63         LEDOUT:
  64         ldi r21,0xff
  65         sub r21,r17
  66         out PORTA,r21
  67         out PORTB,r21
  68         out PORTC,r21
  69         out PORTD,r21
  70
  71         ; get the number we want to transmit
  72         mov r19,r17
  73         ldi r20,0x30 ; ascii 0
  74         GETNUMBER:
  75
  76                 lsr r19
  77                 inc r20
  78                 cpi r19,0
  79                 brne GETNUMBER
  80
  81         ; uart transmit
  82         UARTOUT:
  83
  84                 ; try again if uart not ready
  85                 sbis UCSRA,UDRE
  86                 rjmp UARTOUT
  87
  88         ; transmit the number
  89         out UDR,r20
  90
  91         ; loop forever
  92         rjmp LOOP
  93
  94 ; eof