Raspi I2c IOError: [Errno 121] Remote I/O error

Question

I'm trying to get data from i2c but it shows with IOError: [Errno 121] Remote I/O error . I would know which part went wrong and how to fix it.

import time
import smbus
import math

# define BMP388 Device I2C address
I2C_ADD_BMP388_AD0_LOW    =    0x76
I2C_ADD_BMP388_AD0_HIGH    =   0x77
I2C_ADD_BMP388    =        I2C_ADD_BMP388_AD0_LOW

BMP388_REG_ADD_WIA    =    0x00
BMP388_REG_VAL_WIA        =    0x50

BMP388_REG_ADD_ERR    =    0x02
BMP388_REG_VAL_FATAL_ERR    =    0x01
BMP388_REG_VAL_CMD_ERR        =    0x02
BMP388_REG_VAL_CONF_ERR        =    0x04

BMP388_REG_ADD_STATUS    =    0x03
BMP388_REG_VAL_CMD_RDY        =    0x10
BMP388_REG_VAL_DRDY_PRESS    =    0x20
BMP388_REG_VAL_DRDY_TEMP    =    0x40

BMP388_REG_ADD_CMD    =    0x7E
BMP388_REG_VAL_EXTMODE_EN    =    0x34
BMP388_REG_VAL_FIFI_FLUSH    =    0xB0
BMP388_REG_VAL_SOFT_RESET    =    0xB6

BMP388_REG_ADD_PWR_CTRL    =    0x1B
BMP388_REG_VAL_PRESS_EN        =    0x01
BMP388_REG_VAL_TEMP_EN        =    0x02
BMP388_REG_VAL_NORMAL_MODE    =    0x30

BMP388_REG_ADD_PRESS_XLSB    =    0x04
BMP388_REG_ADD_PRESS_LSB    =    0x05
BMP388_REG_ADD_PRESS_MSB    =    0x06
BMP388_REG_ADD_TEMP_XLSB    =    0x07
BMP388_REG_ADD_TEMP_LSB        =    0x08
BMP388_REG_ADD_TEMP_MSB        =    0x09

BMP388_REG_ADD_T1_LSB    =    0x31
BMP388_REG_ADD_T1_MSB    =    0x32
BMP388_REG_ADD_T2_LSB    =    0x33
BMP388_REG_ADD_T2_MSB    =    0x34
BMP388_REG_ADD_T3        =    0x35
BMP388_REG_ADD_P1_LSB    =    0x36
BMP388_REG_ADD_P1_MSB    =    0x37
BMP388_REG_ADD_P2_LSB    =    0x38
BMP388_REG_ADD_P2_MSB    =    0x39
BMP388_REG_ADD_P3        =    0x3A
BMP388_REG_ADD_P4        =    0x3B
BMP388_REG_ADD_P5_LSB    =    0x3C
BMP388_REG_ADD_P5_MSB    =    0x3D
BMP388_REG_ADD_P6_LSB    =    0x3E
BMP388_REG_ADD_P6_MSB    =    0x3F
BMP388_REG_ADD_P7        =    0x40
BMP388_REG_ADD_P8        =    0x41
BMP388_REG_ADD_P9_LSB    =    0x42
BMP388_REG_ADD_P9_MSB    =    0x43
BMP388_REG_ADD_P10        =    0x44
BMP388_REG_ADD_P11        =    0x45

class BMP388(object):
    """docstring for BMP388"""
    def __init__(self, address=I2C_ADD_BMP388):
        self._address = address
        self._bus = smbus.SMBus(1)
        # Load calibration values.
        if self._read_byte(BMP388_REG_ADD_WIA) == BMP388_REG_VAL_WIA:
            print("Pressure sersor is BMP388!\r\n")    
            u8RegData = self._read_byte(BMP388_REG_ADD_STATUS)
            if ( u8RegData & BMP388_REG_VAL_CMD_RDY ):
                self._write_byte(BMP388_REG_ADD_CMD, BMP388_REG_VAL_SOFT_RESET) 
                time.sleep(0.01)
        else:
            print("Pressure sersor NULL!\r\n")
        self._write_byte( BMP388_REG_ADD_PWR_CTRL,BMP388_REG_VAL_PRESS_EN | BMP388_REG_VAL_TEMP_EN | BMP388_REG_VAL_NORMAL_MODE)
        self._load_calibration()

    def _read_byte(self,cmd):
        return self._bus.read_byte_data(self._address,cmd)

    def _read_s8(self,cmd):
        result = self._read_byte(cmd)
        if result > 128:result -= 256
        return result    

    def _read_u16(self,cmd):
        LSB = self._bus.read_byte_data(self._address,cmd)
        MSB = self._bus.read_byte_data(self._address,cmd+1)
        return (MSB << 8) + LSB

    def _read_s16(self,cmd):
        result = self._read_u16(cmd)
        if result > 32767:result -= 65536
        return result

    def _write_byte(self,cmd,val):
        self._bus.write_byte_data(self._address,cmd,val)

    def _load_calibration(self):
        print("_load_calibration\r\n")
        "load calibration"
        """ read the temperature calibration parameters """
        self.T1 =self._read_u16(BMP388_REG_ADD_T1_LSB)
        self.T2 =self._read_u16(BMP388_REG_ADD_T2_LSB)
        self.T3 =self._read_s8(BMP388_REG_ADD_T3)
        """ read the pressure calibration parameters """
        self.P1 =self._read_s16(BMP388_REG_ADD_P1_LSB)
        self.P2 =self._read_s16(BMP388_REG_ADD_P2_LSB)
        self.P3 =self._read_s8(BMP388_REG_ADD_P3)
        self.P4 =self._read_s8(BMP388_REG_ADD_P4)
        self.P5 =self._read_u16(BMP388_REG_ADD_P5_LSB)
        self.P6 =self._read_u16(BMP388_REG_ADD_P6_LSB)
        self.P7 =self._read_s8(BMP388_REG_ADD_P7)
        self.P8 =self._read_s8(BMP388_REG_ADD_P8)
        self.P9 =self._read_s16(BMP388_REG_ADD_P9_LSB)    
        self.P10 =self._read_s8(BMP388_REG_ADD_P10)
        self.P11=self._read_s8(BMP388_REG_ADD_P11)
    def compensate_temperature(self,adc_T):
        partial_data1 =  (adc_T - (256 *  (self.T1)))
        partial_data2 =  (self.T2 * partial_data1)
        partial_data3 =  (partial_data1 * partial_data1)
        partial_data4 =  (( partial_data3) * ( self.T3))
        partial_data5 = ( (( partial_data2) * 262144) +  partial_data4)
        partial_data6 =  (( partial_data5) / 4294967296)
        self.T_fine = partial_data6
        comp_temp =  ((partial_data6 * 25)  / 16384)
        return comp_temp;

    def compensate_pressure(self,adc_P):
        partial_data1 = self.T_fine * self.T_fine
        partial_data2 = partial_data1 / 64
        partial_data3 = (partial_data2 * self.T_fine) / 256
        partial_data4 = (self.P8 * partial_data3) / 32
        partial_data5 = (self.P7 * partial_data1) * 16
        partial_data6 = (self.P6 * self.T_fine) * 4194304;
        offset =  ( (self.P5) *  140737488355328) + partial_data4 + partial_data5 + partial_data6

        partial_data2 = (( self.P4) * partial_data3) / 32
        partial_data4 = (self.P3 * partial_data1) * 4
        partial_data5 = ( (self.P2) - 16384) * ( self.T_fine) * 2097152
        sensitivity = (( (self.P1) - 16384) *  70368744177664) + partial_data2 + partial_data4 + partial_data5

        partial_data1 = (sensitivity / 16777216) * adc_P
        partial_data2 =  (self.P10) *  (self.T_fine)
        partial_data3 = partial_data2 + (65536 *  (self.P9))
        partial_data4 = (partial_data3 * adc_P) / 8192
        partial_data5 = (partial_data4 * adc_P) / 512
        partial_data6 =  ( adc_P *  adc_P)
        partial_data2 = ( (self.P11) *  (partial_data6)) / 65536
        partial_data3 = (partial_data2 * adc_P) / 128
        partial_data4 = (offset / 4) + partial_data1 + partial_data5 + partial_data3
        comp_press = (( partial_data4 * 25) /  1099511627776)
        return comp_press;

    def get_temperature_and_pressure_and_altitude(self):
        """Returns pressure in Pa as double. Output value of "6386.2"equals 96386.2 Pa = 963.862 hPa."""
        xlsb = self._read_byte(BMP388_REG_ADD_TEMP_XLSB)
        lsb =  self._read_byte(BMP388_REG_ADD_TEMP_LSB)
        msb =  self._read_byte(BMP388_REG_ADD_TEMP_MSB)
        adc_T = (msb << 16) + (lsb << 8) + (xlsb)
        temperature = self.compensate_temperature(adc_T)
        xlsb = self._read_byte(BMP388_REG_ADD_PRESS_XLSB)
        lsb =  self._read_byte(BMP388_REG_ADD_PRESS_LSB) 
        msb =  self._read_byte(BMP388_REG_ADD_PRESS_MSB) 

        adc_P = (msb << 16) + (lsb << 8) + (xlsb)
        pressure = self.compensate_pressure(adc_P)
        altitude  = 4433000 * (1 - pow(((pressure/100.0) / 101325.0), 0.1903)) 

        return temperature,pressure,altitude

if __name__ == '__main__':
    import time
    
    print(" Test start ...\n")
    
    bmp388 = BMP388()
    try:
        while True:
            time.sleep(0.5)
            temperature,pressure,altitude = bmp388.get_temperature_and_pressure_and_altitude()
            print(' Temperature = %.1f Pressure = %.2f  Altitude =%.2f '%(temperature/100.0,pressure/100.0,altitude/100.0))
    except IOError as e:
        print("IO error detected")
        print(e)
    
    except KeyboardInterrupt:
        print("End of program")
        print("ctrl + c:")
        exit()

Here is complete error tracing:

python test.py 
Test start ...

Traceback (most recent call last):
  File "test.py", line 193, in <module>
    bmp388 = BMP388()
  File "test.py", line 68, in __init__
    if self._read_byte(BMP388_REG_ADD_WIA) == BMP388_REG_VAL_WIA:
  File "test.py", line 80, in _read_byte
    return self._bus.read_byte_data(self._address,cmd)
IOError: [Errno 121] Remote I/O error

Answer 1

For anyone that lands out this. I was able to fix IOError: [Errno 121] Remote I/O error. I used i2cdetect -y 1 and it was showing a device but it kept getting [Errno 121]. I changed from using a breadboard to directly connecting the device. Something with the connection in through the breadboard was messing up the signal.