ADC Usage Tutorial#

What is ADC?#

ADC (Analog-to-Digital Converter) is a hardware module that converts analog signals (such as voltage) into digital signals. In embedded systems, the ADC serves as a bridge between sensors and microprocessors, used to collect voltage signals and convert them into computable numerical data.

The K230 chip integrates a high-performance ADC module internally, with the following features:

Supports 6 independent channels
Resolution: 12-bit (i.e., output value range is 0~4095)
Sampling rate up to 1 MHz
Output format: raw value (read_u16()) or voltage (read_uv(), unit: microvolts)

Example Overview#

The following example demonstrates how to read the sample value and voltage value of the ADC channel through the interface provided by K230, for subsequent signal processing or sensor data acquisition.

Import module and initialize ADC#

from machine import ADC

# Instantiate ADC channel 0
adc = ADC(0)

Read raw sample value (unit: dimensionless)#

# Read the raw sample value of channel 0 (0 ~ 4095)
value = adc.read_u16()
print("ADC raw value:", value)

Return value range: 0~4095
Represents the ratio of the input voltage to the reference voltage
Can be used for digital signal processing, threshold judgment, and other scenarios

Read voltage value (unit: microvolts)#

# Read the voltage value of channel 0, unit is uV
voltage = adc.read_uv()
print("ADC voltage value:", voltage, "uV")

Return unit: microvolts (μV)
Provides more intuitive actual voltage information, convenient for corresponding with circuit or sensor parameters
If volts (V) are needed as the unit, divide by 1_000_000

Example output (assuming input is 1.65V)#

ADC raw value: 2047
ADC voltage value: 1650000 uV

Resolution and Voltage Mapping#

The K230 ADC has a 12-bit resolution, and the relationship between the sampled value and the actual voltage is linear:

\[ V_{in} = \frac{\text{ADC\_Value}}{4095} \times V_{\text{ref}} \]

⚠️ The default reference voltage is generally 3.3V, depending on the chip configuration

Notes#

Item	Description
Channel Number	Supports 6 channels (numbered 0~5), please ensure that the pin corresponding to the connected channel has the analog input function
Input Voltage Range	The maximum input must not exceed the reference voltage (e.g., 3.3V), otherwise the chip may be damaged
Unit Conversion	`read_u16()` returns the raw sampled value; `read_uv()` returns the actual voltage (μV)
Sampling Noise	It is recommended to average multiple readings to reduce the transient jitter of ADC sampling and the impact of external interference

Application Scenarios#

Voltage detection (e.g., battery voltage, power status)
Analog sensor reading (e.g., temperature, potentiometer, photoresistor)
Sampling of analog signals such as audio and vibration
Analog signal monitoring in feedback control systems

ADC Usage Tutorial

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