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                         ldi r23,0
  41                         IILOOP:
  42                                 inc r23
  43                                 cpi r23,0x40
  44                                 brne IILOOP
  45
  46                         inc r22
  47                         cpi r22,0xff
  48                         brne INNERLOOP
  49
  50                 ; increase loop counter
  51                 inc r18
  52
  53                 ; check loop counter
  54                 cpi r18,0xff
  55
  56                 ; continue if loop counter = 0xff
  57                 ; else do loop again
  58                 brne LOOP
  59
  60         ; shift the led counter
  61         lsl r17
  62
  63         ; set first bit if led counter is equal zero
  64         cpi r17,0
  65         brne LEDOUT
  66         ldi r17,1
  67
  68         ; drive the leds
  69         LEDOUT:
  70         ldi r21,0xff
  71         sub r21,r17
  72         out PORTA,r21
  73         out PORTB,r21
  74         out PORTC,r21
  75         out PORTD,r21
  76
  77         ; get the number we want to transmit
  78         mov r19,r17
  79         ldi r20,0x30 ; ascii 0
  80         GETNUMBER:
  81
  82                 lsr r19
  83                 inc r20
  84                 cpi r19,0
  85                 brne GETNUMBER
  86
  87         ; uart transmit
  88         UARTOUT:
  89
  90                 ; try again if uart not ready
  91                 sbis UCSRA,UDRE
  92                 rjmp UARTOUT
  93
  94         ; transmit the number
  95         out UDR,r20
  96
  97         ; loop forever
  98         rjmp LOOP
  99
 100 ; eof