code_seg segment code data_seg segment data stack_seg segment idata spk bit p1.3 rseg data_seg frq:ds 1 tmp:ds 1 rseg stack_seg stack:ds 20 cseg at 00000h ljmp main cseg at 0003h ljmp zd rseg code_seg jmp main PORTA EQU 8FFFH ;8255A口地址 PORTB EQU 9FFFH ;8255B口地址 PORTC EQU 0AFFFH ;