copilot

• MCP3008 VDD to Raspberry Pi 3.3V
• MCP3008 VREF to Raspberry Pi 3.3V
• MCP3008 AGND to Raspberry Pi GND
• MCP3008 DGND to Raspberry Pi GND
• MCP3008 CLK to Raspberry Pi SCLK
• MCP3008 DOUT to Raspberry Pi MISO
• MCP3008 DIN to Raspberry Pi MOSI
• MCP3008 CS/SHDN to Raspberry Pi CE0

Python
import spidev
import time

# Open SPI bus
spi = spidev.SpiDev()
spi.open(0,0)
spi.max_speed_hz = 1000000

# Function to read SPI data from MCP3008 chip
# Channel must be an integer 0-7
def read_channel(channel):
    val = spi.xfer2([1, (8 + channel) << 4, 0])
    data = ((val[1] & 3) << 8) + val[2]
    return data

# Function to convert data to voltage level
# considering a Vref of 3.3V for MCP3008
def convert_to_voltage(data, Vref = 3.3):
    return (data * Vref) / float(1023)

# Define sensor channel (we'll use channel 0)
sensor_channel = 0

# Define the delay between each reading
delay = 1

while True:
    # Read the sensor data
    sensor_data = read_channel(sensor_channel)
    # Convert the data to voltage
    sensor_voltage = convert_to_voltage(sensor_data)
    
    print("Channel {} Data: {}, Voltage: {:.2f}V".format(sensor_channel, sensor_data, sensor_voltage))
    
    # Delay before the next reading
    time.sleep(delay)

• This example reads from channel 0 of the MCP3008. To read from other channels, change the sensor_channel variable accordingly.
• The read_channel function initiates an SPI transfer to read the data from a specific channel of the MCP3008.
• The convert_to_voltage function converts the raw data (which will be in the range 0-1023 for a 10-bit ADC like the MCP3008) into a voltage, taking into account the reference voltage (Vref) provided to the MCP3008. For this example, it is assumed that Vref is 3.3V, which is typical for Raspberry Pi projects.
• Ensure spidev is installed on your Raspberry Pi (pip install spidev).

copilot

Bash
pip install spidev

Python
import spidev
import time

# Create an SPI instance on bus 0, device 0
spi = spidev.SpiDev()
spi.open(0, 0)

# MCP3550 settings
spi.max_speed_hz = 1000000  # 1 MHz
spi.mode = 0  # Polarity = 0, Phase = 0

def read_mcp3550():
    # Perform a read operation
    # The MCP3550 requires a dummy byte to initiate communication.
    # Response is in 3 bytes for MCP3550-60 and MCP3550-50.
    response = spi.xfer2([0x00, 0x00, 0x00])
    
    # Combine the three bytes by shifting
    result = (response[0] << 16) | (response[1] << 8) | response[2]

    # For MCP3550-60, the result is in 24 bits, where the first bit is the sign bit.
    # Adjusting the result if the sign bit is set.
    if result & 0x800000:
        result -= 0x1000000
    
    return result

try:
    while True:
        # Read data from MCP3550
        data = read_mcp3550()
        print("Raw ADC Value: ", data)
        
        # Convert the raw value to voltage
        # Assuming Vref is 5V and considering the 24-bit resolution
        voltage = (data * 5.0) / (2**24)
        print("Voltage: {:.4f} V".format(voltage))
        
        # Sample rate control - MCP3550 has a typical conversion time
        time.sleep(1)
except KeyboardInterrupt:
    spi.close()