System for digitally emulating the analog position of a PC game port joystick

A universal system for providing representations of the setting of an analog joystick potentiometer including in combination:

• an analog-to-digital converter having an input coupled with a source of analog signals from said joystick potentiometer and having a digital output;
• a digital counter coupled to the output of said analog-to-digital converter to receive signals therefrom and providing parallel digital outputs representative of the count therein and further having another output representative of an initial count therein;
• a control circuit coupled with said digital counter to load said counter with the output from said analog-to-digital converter at a predetermined time;
• a joystick position gate circuit coupled with the digital outputs of said counter for supplying said outputs when said joystick gate circuit is enabled;
• a countdown circuit coupled with the countdown output of said counter for producing an output signal whenever said countdown circuit is enabled and a signal representative of said initial count appears on said another output of said counter;
• a source of mode control signals coupled with said control circuit for causing said control circuit to operate said counter in a countdown mode in a first mode of operation and to operate as a data latch in a second mode of operation;
• and
• a clock circuit coupled with said control circuit for supplying clock pulses thereto, with said clock pulses being supplied to said counter by said control circuit in said first mode of operation to cause said counter to count down to an initial value to produce an output signal on said another output thereof when said countdown to said initial value is attained, with said control circuit operated in said first mode of operation, said control circuit in said second mode of operation enabling said joystick gate circuit at a second predetermined time.