`bpi-cm5-spi-thermal-sensor-read-10.ino`

Banana Pi BPI-CM5: Amlogic A311D2 Compute Module with Raspberry Pi CM4 Compatibility · File : bpi-cm5-spi-thermal-sensor-read-10.ino · Language : python · Use case : Lire un capteur de température numérique connecté via l'interface SPI pour la surveillance thermique.

Python example using the spidev library to read a digital temperature sensor (MCP9808/TMP102) via the BPI-CM5 SPI bus.

This script requires enabling the SPI interface in the OS (via armbian-config or Device Tree overlay). Install 'python3-spidev'. The code is adapted for the default SPI bus of the Amlogic A311D2. Verify the presence of /dev/spidev1.0. Ensure the sensor is correctly wired (CLK, MOSI, MISO, GND).

bpi-cm5-spi-thermal-sensor-read-10.ino

import spidev
import time
import sys

# SPI Settings for BPI-CM5 Amlogic A311D2
# Usually bus 1, device 0 (check /dev/spidev1.0)
SPI_BUS = 1
SPI_DEV = 0
SPI_SPEED = 1000000 # 1 MHz

def read_temperature_mcp9808(spi):
    """
    Reads temperature from MCP9808.
    Address 0x30, Command 0x05 (Ambient Temperature)
    """
    try:
        # Send command to read ambient temperature
        msg = [0x05]
        spi.xfer2(msg)
        
        # Read 2 bytes of data
        resp = spi.xfer2([0x00, 0x00])
        
        # Combine MSB and LSB
        raw_temp = (resp[0] << 8) | resp[1]
        
        # Handle sign bit (13th bit)
        if raw_temp & 0x2000:
            temp = -raw_temp & 0x1FFF
            temp = temp / 256.0
        else:
            temp = (raw_temp & 0x1FFF) / 256.0
            
        return temp
    except Exception as e:
        print(f"SPI Error: {e}")
        return None

try:
    spi = spidev.SpiDev()
    spi.open(SPI_BUS, SPI_DEV)
    spi.max_speed_hz = SPI_SPEED
    spi.mode = 0
    
    print(f"Reading MCP9808 Temperature on SPI{SPI_BUS}.{SPI_DEV}...")
    
    while True: 
        temp = read_temperature_mcp9808(spi)
        if temp is not None:
            print(f"Temperature: {temp:.2f} C")
        time.sleep(1)
        
except KeyboardInterrupt:
    print("\nExiting...")
except FileNotFoundError:
    print("Error: SPI device not found. Enable SPI in Armbian config (armbian-config).")
except Exception as e:
    print(f"Unexpected error: {e}")
finally:
    if 'spi' in locals():
        spi.close()

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