锁相环mb1504例程，方便快捷使用1504进行锁相-PLL mb1504 routine, convenient to use 1504 for lock

MB1504 51单片机的控制程序，经测试可用，里面有三个1504程序，可以步进频率，用矩阵键盘任意输入频率，用12864液晶显示-MB1504 51 MCU control procedures have been tested, there are three 1504 program, you can step frequency, using an arbitrary matrix keyboard input frequency, with LCD 12864