This class is designed for GPIO simulating standard I2C protocol. Except for creating the object, all other operations (read and write) are consistent with I2C communication.

Constructor

machine.I2C_simulation

class machin.I2C_simulation(GPIO_clk, GPIO_sda, CLK)

Parameter:

• GPIO_clk - Integer type. CLK pin of I2C (See definitions in machine.Pin for GPIO pin numbers that need to be controlled).
• GPIO_sda - Integer type. SDA pin of I2C (See definitions in machine.Pin for GPIO pin numbers that need to be controlled).
• CLK - Integer type. Frequency of I2C. Range: [1, 1000000 Hz].

Example:

>>> from machine import I2C_simulation
>>> # Creates an I2C_simulation object
>>> i2c_obj = I2C_simulation(I2C_simulation.GPIO10, I2C_simulation.GPIO11, 300)  # Returns an I2C object

Methods

I2C_simulation.read

I2C_simulation.read(slaveaddress, addr,addr_len, r_data, datalen, delay)

This method reads data to I2C bus.

Parameter:

• slaveaddress - Integer type. I2C device address.
• addr - Bytearray type. I2C register address.
• addr_len - Integer type. Register address length.
• r_data - Bytearray type. Byte array used to receive data.
• datalen - Integer type. Length of byte array.
• delay - Integer type. Delay. Data conversion buffer time (unit: ms).

Return Value:

0 - Successful execution

-1 - Failed execution

I2C_simulation.write

I2C_simulation.write(slaveaddress, addr, addr_len, data, datalen)

This method writes data to I2C bus.

Parameter:

• slaveaddress - Integer type. I2C device address.
• addr - Bytearray type. I2C register address.
• addr_len - Integer type. Register address length.
• data - Bytearray type. Data to be written.
• datalen - Integer type. Length of data to be written.

Return Value:

0 - Successful execution

-1 - Failed execution

Example:

import log
#from machine import I2C
from machine import I2C_simulation
import utime as time
"""
1. calibration
2. Trigger measurement
3. read data
"""

# API  manual
# https://python.quectel.com/doc/API_reference/en/peripherals/machine.I2C_simulation.html

# AHT10 instructions
# https://server4.eca.ir/eshop/AHT10/Aosong_AHT10_en_draft_0c.pdf
# This example shows that driver AHT10 obtains temperature and humidity data.

class aht10class():
    i2c_log = None
    i2c_dev = None
    i2c_addre = None

    # Initialization command
    AHT10_CALIBRATION_CMD = 0xE1
    # Trigger measurement
    AHT10_START_MEASURMENT_CMD = 0xAC
    # reset
    AHT10_RESET_CMD = 0xBA

    def write_data(self, data):
        self.i2c_dev.write(self.i2c_addre,
                           bytearray(0x00), 0,
                           bytearray(data), len(data))
        pass

    def read_data(self, length):
        print("read_data start")
        r_data = [0x00 for i in range(length)]
        r_data = bytearray(r_data)
        print("read_data start1")
        ret = self.i2c_dev.read(self.i2c_addre,
                          bytearray(0x00), 0,
                          r_data, length,
                          0)
        print("read_data start2")
        print('ret',ret)
        print('r_data:',r_data)
        return list(r_data)

    def aht10_init(self, addre=0x38, Alise="Ath10"):
        self.i2c_log = log.getLogger(Alise)
        self.i2c_dev = I2C_simulation(I2C_simulation.GPIO10, I2C_simulation.GPIO11, 300)
        self.i2c_addre = addre
        self.sensor_init()
        pass

    def aht10_transformation_temperature(self, data):
        r_data = data
        #　Convert the temperature according to descriptions in the data manual 
        humidity = (r_data[0] << 12) | (
            r_data[1] << 4) | ((r_data[2] & 0xF0) >> 4)
        humidity = (humidity/(1 << 20)) * 100.0
        print("current humidity is {0}%".format(humidity))
        temperature = ((r_data[2] & 0xf) << 16) | (
            r_data[3] << 8) | r_data[4]
        temperature = (temperature * 200.0 / (1 << 20)) - 50
        print("current temperature is {0}°C".format(temperature))


    def sensor_init(self):
        # calibration
        self.write_data([self.AHT10_CALIBRATION_CMD, 0x08, 0x00])
        time.sleep_ms(300)  # At least 300 ms
        pass


    def ath10_reset(self):
        self.write_data([self.AHT10_RESET_CMD])
        time.sleep_ms(20)  # At least 20 ms

    def Trigger_measurement(self):
        # Trigger data conversion
        self.write_data([self.AHT10_START_MEASURMENT_CMD, 0x33, 0x00])
        time.sleep_ms(200)  # At least delay 75 ms
        # check has success
        r_data = self.read_data(6)
        # check bit7
        if (r_data[0] >> 7) != 0x0:
            print("Conversion has error")
        else:
            self.aht10_transformation_temperature(r_data[1:6])

ath_dev = None

def i2c_aht10_test():
    global ath_dev
    ath_dev = aht10class()
    ath_dev.aht10_init()

    # Test ten times
    for i in range(5):
        ath_dev.Trigger_measurement()
        time.sleep(1)


if __name__ == "__main__":
    print('start')
    i2c_aht10_test()

I2C - Two-wire Serial Protocol

SPI - Serial Peripheral Interface Bus Protocol