51单片机按键加减清零汇编语言编程答:#00HMAIN1:CALL CONVTCALL PLAYCALL KEY_PROGJMP MAIN1KEY_PROG:CALL K_SCAN ;键扫描MOV A,K_NEWCJNE A,K_OLD,KEY_P1JMP KEY_P_ENDKEY_P1:MOV K_OLD,ACJNE A,#1, NEXT_K1AJMP LOOP1NEXT_K1:CJNE A,#2, NEXT_K2AJMP LOOP2NEXT_K2:CJNE A,#3, KEY_P_ENDAJMP L...