Joypad circuit for playing PC games

A programmable joypad for playing PC games comprising:

• a panel having a plurality of control buttons, a directional button, a switching button, a mode selecting switch, a four/eight direction mode switch, a setting switch;
• and
• a control circuit having a microprocessor, a memory, a switching circuit, and a parallel/serial conversion circuit, wherein
• said microprocessor has a plurality of input and output pins respectively coupled with said control buttons, said directional button, said switching button, and mode selecting switch, and setting switch, a data input pin coupled to the PC, a clock pin coupled to the PC, a set pin coupled to said parallel/serial conversion circuit via the direction mode switch, the setting switch, and a control pin coupled to the switch circuit, which is composed of a first transistor having a collector connected to a clock pin of a keyboard, an emitter connected the clock pin of the microprocessor, and a base respectively connected to the control pin of the microprocessor and a clock line of the keyboard via a diode and a second transistor having a collector connected to the data line of the keyboard, a base connected to the base of the first transistor, and an emitter connected to the data pin of the microprocessor.