可预置可逆4位计数器



利用AT89S51单片机的P1.0－P1.3接四个发光二极管L1－L4，用来指示当前计数的数据；用P1.4－P1.7作为预置数据的输入端，接四个拨动开关K1－K4，用P3.6/WR和P3.7/RD端口接两个轻触开关，用来作加计数和减计数开关

-be reversible four preset counter use AT89S51 SCM P1.0 - P1.3 then made 4 LED L1 - L4, used to indicate the current count data; with P1.4 - P1.7 as preset data input and then flicking a switch four K1 - K4. with P3.6/WR P3.7/RD ports and then two touch switches, used for counting and increases by counting Switches