On power up, the firmware starts executing code at address 0h. After some housekeeping tasks it will determine whether it is attached to a USB or a PS2 interface. From that, it will branch either to USB_Main or PS2_Main. -On power up, the

键盘通讯测试工具软件，兼容各种键盘，USB ps2不限。-keyboard test program, you can use it to test all kinds of keyboard,include USB or PS2.