usarttran.asm.bak

USART异步串行发送例程

;***************************usart transmit************************
;*
;* title      :    usart transmit
;* version    :    V01
;* target     :    attiny2313
;* osc        :    8MHz
;* Create data:    2007.01.09
;* Last updata:    2007.01.09
;* Author     :    sonic
;*
;******************************************************************
.include"tn2313def.inc"
.list

.def    temp =  r16
;*
;************************program code******************************
.org    $0000
      rjmp    reset      ; reset port
      reti               ; external interrupt request 0
      reti               ; external interrupt request 1
      reti               ; Timer/counter 1 capture event
      reti               ; Timer/counter 1 compare match A
      reti               ; Timer/counter 1 overflow
      reti               ; Timer/counter 0 overflow
      reti               ; Usart0, Rx complete
      reti               ; Usart0 data regrister empty
      reti               ; Usart0 Tx complete
      reti               ; analog comparator
      reti               ; Pin charge interrupt
      reti               ; Timer/counter 1 compare match B
      reti               ; Timer/counter 0 compare match A
      reti               ; Timer/counter 0 compare match B
      reti               ; USI start condition
      reti               ; USI overflow
      reti               ; EEPROM ready
      reti               ; Watchdog Timer overflow
.org    $0014
reset:
      ldi    temp,  low(ramend)        ;set stack address
      out    spl,  temp
      clr    temp
      out    ddrb,  temp
      ser    temp
      out    portb,  temp
      ldi    temp,  0x00
	  out    ubrrh,  temp
	  ldi    temp,  51
	  out    ubrrl,  temp     ;  set ubrr 
	  ldi    temp,  (1<<txen)
	  out    ucsrb,  temp
	  ldi    temp,  (1<<usbs)|(1<<ucsz1)|(1<<ucsz0)
	  out    ucsrc,  temp
	  nop
	  nop
	  nop
wait:
      sbis    ucsra,  udre
	  rjmp    wait
	  in    temp,  pinb
	  out    udr,  temp
	  nop
	  nop
      rjmp    wait