ADCn

ADCn, short for analog-to-digital converter n, is a generic label used in microcontroller and system-on-chip documentation to denote the nth ADC peripheral installed on the device. It is not a specific product, but a placeholder that distinguishes multiple converters, such as ADC1, ADC2, and ADC3, within a single chip.

An ADC converts an analog voltage on one of its input channels to a digital code that represents the voltage within a reference range, typically 0 to Vref. The output code size defines resolution (for example, 8, 12, or 16 bits); accuracy depends on design, drift, and calibration. Converters may share an input multiplexer and sampling capacitor, with channels selected by software or hardware triggers. Conversions can be single-shot or continuous, and data are usually read from a data register, often with support for direct memory access (DMA).

Architectures and performance vary by device. Common MCU ADCs use successive-approximation-register (SAR) architectures for good speed and power balance, while delta-sigma converters provide higher resolution at slower speeds. Features such as sampling time, input impedance, differential inputs, internal reference options, and programmable gain amplifiers may be present. Many ADCn blocks also include analog features like temperature sensors, analog watchdogs, and reference management.

In firmware, ADCn is enabled and configured for a specific channel, sampling time, and trigger source; a conversion is started and the result is read from a data register, with DMA often handling transfers. Calibration and proper input conditioning are important for accuracy.

See also: analog-to-digital converter, microcontroller, ADC resolution, sampling rate, DMA.