Basic
GPIO
A digital pin configurable as an input or output.
In industrial practice
The chip total is not the number of free board pins; flash, PSRAM and strapping functions may reserve them.
Related:PinoutStrapping pinsOpen-drain
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TECHNICAL GLOSSARY
Peripherals
GPIO, converters and serial buses: the interfaces through which the ESP32 talks to sensors, actuators and displays.
terms in this category
Basic
ADC
An analog-to-digital converter that turns voltage into a numeric value.
In industrial practice
4–20 mA and 0–10 V signals require conditioning, protection and calibration.
Basic
DAC
A digital-to-analog converter that produces a voltage level from a digital value.
In industrial practice
The internal DAC does not directly provide a 0–10 V industrial signal.
Basic
PWM
Pulse-width modulation that controls the duty cycle of a digital signal.
In industrial practice
It can control power or generate a filtered average level, but it does not replace a precise analog output.
Basic
UART
An asynchronous serial interface with transmit and receive lines.
In industrial practice
UART operates at logic levels; RS-232 and RS-485 require dedicated transceivers.
Related:RS-485RS-232Modbus RTU
Basic
SPI
A fast synchronous serial bus with a clock and individual device selection.
In industrial practice
It is used by displays, memory and external Ethernet; length and signal integrity matter.
Basic
I²C
A two-wire serial bus with addressing and open-drain lines.
In industrial practice
It requires pull-up resistors and should remain short in noisy environments.
Related:SPIOpen-drain
Intermediate
I²S
A serial interface intended for digital audio and synchronous samples.
In industrial practice
It can connect codecs, microphones and converters for continuous acquisition.