test_pin.asm

串口通信 频率测量 EEPROM读写程序

     .include "c:\appnotes\8515def.inc"      
        .org $00d
  start:   ldi r17,0b11111100
           out SPCR,r17  ;set SPE,MSTR,CPOL,CPHA ,reset the others
           out DDRB,r16 ;portb is output mode and turn off all LEDS                           
           sbi DDRB,5    ;set MOSI(PB.5) output mode whwn SPI is master.
           sbi DDRB,7    ;set SCK (PB.7) output mode when SPI is master
           sbi DDRB,4   
           clr r17
           out SPDR,r17  ;cle
           ldi r17,$01
           out PORTB,r17  
    ; wait: sbis SPSR,7
     ;      rjmp wait
           rjmp start