FPGA DC Motor Control

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Trimpot Input To The MAX150 Interface
           The MAX150 will be used in its WR mode, which means we only have to send a single pulse to the WR pin to tell the A/D to start a conversion. The process from power up to displaying PWM digital output on the LEDs can be seen in the simplified float chart below. As soon as the LEDs see the PWM pulse, the motor controller sees it as well.

           The A/D conversion process is a pulsed function, which means it converts, outputs the digital value and then starts over again by pulsing the A/D WR pin to convert, then getting the new value and updating the PWM output register, until infinity.

Analog To Digital
           The MAX150 takes in an analog voltage between two reference voltages. Then this value is converted to a magnitude value in an 8 bit digital format. The chart belows gives one example for how to calculate what digital value to expect, given a specific analog voltage input.

           The two reference voltages seen above, Vref+ and Vref- are the same as we'll be using for this project, +5.0v and +0.0v respectively. So you can plug in any analog voltages to the formula and see what the digital equivalent will turn out to be. Then after building this project you can verify that your system is working correctly with this theory.