Quick Start

Following example code shows how the driver is intended to use:

import time
from sensirion_shdlc_driver import ShdlcSerialPort, ShdlcConnection
from sensirion_shdlc_sensorbridge import SensorBridgePort, SensorBridgeShdlcDevice

# Connect to the device with default settings:
#  - baudrate:      460800
#  - slave address: 0
with ShdlcSerialPort(port='COM1', baudrate=460800) as port:
    device = SensorBridgeShdlcDevice(ShdlcConnection(port), slave_address=0)

    # Print some device information
    print("Version: {}".format(device.get_version()))
    print("Product Name: {}".format(device.get_product_name()))
    print("Serial Number: {}".format(device.get_serial_number()))

    # Enable port 1 with an I2C frequency of 400kHz and a voltage of 1.8V
    device.set_i2c_frequency(SensorBridgePort.ONE, frequency=400e3)
    device.set_supply_voltage(SensorBridgePort.ONE, voltage=1.8)
    device.switch_supply_on(SensorBridgePort.ONE)

    # Perform synchronous I2C transceive on port 1
    rx_data = device.transceive_i2c(
        SensorBridgePort.ONE, address=0x70, tx_data=[0x78, 0x66],
        rx_length=6, timeout_us=100e3)
    print("Received data: {}".format(rx_data))

    # Perform asynchronous I2C transceive on port 1
    handle = device.start_repeated_i2c_transceive(
        SensorBridgePort.ONE, interval_us=10e3, address=0x70,
        tx_data=[0x78, 0x66], rx_length=6, timeout_us=100e3, read_delay_us=10e3)
    time.sleep(1.0)  # let the device perform the repeated transceives
    buffer = device.read_buffer(handle)
    device.stop_repeated_i2c_transceive(handle)
    print("Lost bytes: {}".format(buffer.lost_bytes))
    print("Remaining bytes: {}".format(buffer.remaining_bytes))
    print("Buffered values: {}".format([value.data for value in buffer.values]))

Note

The sent I2C frame in this example is the “measure” command of Sensirion’s SHTC3 sensor and its response contains the measured temperature, relative humidity and their checksums. If there is no SHTC3 connected to the SensorBridge, the I2C commands will fail.