3.Analog Input(ADC)
Description
Read the analog value from the specified IO pin.
- UNIHIKER supports 8-channel 12-bit high-precision analog input ADC, which means it will map the input voltage between 0 and 3.3V to an integer value between 0 and 4095.
- These pins support ADC function: P0, P1, P2, P3, P4, P10, P21, P22.
Common functions
There are two ways to implement analog input, one is to use the read_analog() function of the Pin class, and the other is to use the read() function in the independent ADC class.
1.1 Pin( )
| Syntax | PinObject = Pin(Pin.num, Pin.ANALOG) |
| Description | Set the specified pin to ANALOG mode. |
| Parameters | Pin.num: Pin number. (P0, P1, P2, P3, P4, P10, P21, P22) |
| Pin.ANALOG: ANALOG mode. |
| Return | Pin object |
1.2 read_analog( )
| Syntax | PinObject.read_analog() |
| Description | Call the Pin object to read the analog value. |
| Parameters | **None |
| Return | Digital quantity converted from analog quantity. (0~4095) |
1.3 ADC(Pin( ))
| Syntax | AdcObject = ADC(Pin(Pin.num)) |
| Description | Generate an ADC class object for the specified pin. |
| Parameters | Pin.num: Pin number. (P0, P1, P2, P3, P4, P10, P21, P22) |
| Return | ADC object |
1.4 read()
| Syntax | AdcObject.read() |
| Description | Call the Pin object to read the analog value. |
| Parameters | **None |
| Return | Digital quantity converted from analog quantity. (0~4095) |
Example Description
Below is a sample code using the PinPong Library to print the analog value of the UNIHIKER P21 pin.
Hardware Required
Example Code
# -*- coding: UTF-8 -*-
# Experiment Effect: Print the analog value of the UNIHIKER P21 pin
# Wiring: Connect a potentiometer module to the UNIHIKER P21 pin
import time
from unihiker.board import Board, Pin ,ADC
Board().begin() # Initialize the UNIHIKER
# ADC analog input pins supported: P0 P1 P2 P3 P4 P10 P21 P22
# adc21 = ADC(Pin(Pin.P21)) # Use Pin object with ADC to enable analog input - Method 1
adc21 = Pin(Pin.P21, Pin.ANALOG) # Initialize the pin as an analog input - Method 2
while True:
# v = adc21.read() # Read the analog signal value from pin A0 - Method 1
v = adc21.read_analog() # Read the analog signal value from pin A0 - Method 2
print("P21 =", v)
time.sleep(0.5) # Wait for 0.5 seconds
