WE ASSUME CONTROL: SPI AND A DIGITAL POTENTIOMETER
In the last video I demonstrated a Universal Active Filter that I could adjust with a dual-gang potentiometer, here I replace the potentiometer with a processor controlled solid-state potentiometer. For those that are too young to remember, we used to say “solid-state” to differentiate between that and something that used vacuum tubes… mostly we meant you could drop it without it breakage.
The most common way to control the everyday peripheral chips available is through use of one of the common Serial Protocols such as I2C and SPI. In the before-time back when we had only 8 bits and were lucky if 7 of them worked, we used to have to memory map a peripheral or Input/Output (I/O) controller which means we had to take many control and data lines from the microprocessor such as Data, Address, Read/Write, system clocks and several other signals just to write to a couple of control registers buried in a chip.
