qt_py_rp2040_ina260_logfile.py

# MicroPython for QT_PY_RP2040 and INA260 boards
import machine
import time

class INA260():

    _INA260_DEVICE_ADDRESS   = 0x44
    _INA260_CONFIG_ADDR      = 0x00
    _INA260_CURRENT_ADDR     = 0x01
    _INA260_BUS_VOLTAGE_ADDR = 0x02
    _INA260_BUS_VOLTAGE_LSB  = 1.25 #mV
    _INA260_CURRENT_LSB      = 1.25 #mA

    # Constructor
    def __init__(self, i2c, i2c_dev_addr=0x44):
        self.i2c_dev_addr = i2c_dev_addr
        self.i2c          = i2c

    def twos_compliment_to_int(self, val, len):
        # Convert twos compliment to integer
        if(val & (1 << len - 1)):
            val = val - (1<<len)
        return val

    def get_bus_voltage(self):
        raw_read = list(self.i2c.readfrom_mem(self.i2c_dev_addr,self._INA260_BUS_VOLTAGE_ADDR,2))
        word_rdata = raw_read[0] *256 + raw_read[1]
        vbus = float(word_rdata) / 1000.0 * self._INA260_BUS_VOLTAGE_LSB
        return vbus

    def get_current(self):
        raw_read   = list(self.i2c.readfrom_mem(self.i2c_dev_addr,self._INA260_CURRENT_ADDR,2))
        word_rdata = raw_read[0] *256 + raw_read[1]
        current_twos_compliment = word_rdata
        current_sign_bit = current_twos_compliment >> 15
        if (current_sign_bit == 1):
            current = float(self.twos_compliment_to_int(current_twos_compliment, 16)) / 1000.0 * self._INA260_CURRENT_LSB
        else:
            current = float(current_twos_compliment) / 1000.0 * self._INA260_CURRENT_LSB
        return current

    def reset_chip(self):
        byte_list = [0x80, 0x00]
        self.i2c.writeto_mem(self.i2c_dev_addr,self._INA260_CONFIG_ADDR,bytearray(byte_list))

def main():
    i2c       = machine.I2C(0,sda=machine.Pin(24),scl=machine.Pin(25),freq=400000) # QT PY RP2040
    ina260    = INA260(i2c=i2c, i2c_dev_addr=0x40)
    f         = open('logfile.csv', 'w')
    last_task = time.time()
    n         = 0
    try:
        while True:
            if (time.time() - last_task) >= 1: # true every 1 seconds
                n += 1 # counts the seconds in the logfile
                voltage = ina260.get_bus_voltage()
                current = ina260.get_current()
                print("{:d},{:.4f},{:.4f}".format(n,voltage,current))
                a = f.write("{:d},{:.4f},{:.4f}\n".format(n,voltage,current)) # assignement avoids printing to console
                last_task=time.time()
            time.sleep(0.5) # this should be half of the repeat interval
    except KeyboardInterrupt:
        f.close()

if __name__ == '__main__':  
   main()