MCS-51单片机的RST引脚除了做为复位信号输入端外，还做为（）的输入端。
A.备用电源
B.振荡信号
C.时钟信号
D.读写信号
参考答案：A
he had wonderful childhood, _____with his mother to all corners of the word
A．travel
B． to travel
C．traveled
D．traveling
简述通过OMCB进行B328版本升级的步骤。
