OSError: [Errno 5] EIO when connecting one ADS1115 module

[chamathkv]

Hi all,

I am working on a project that will be taking readings from multiple ADS1115 modules. I first wanted to try connecting one module to see how it works. My wiring is shown below.

The code I used is very straightforward, and the library I used for the ADS1115 module is from this repo.

from machine import I2C, Pin
import ads1x15

i2c = I2C(0, scl=Pin(17), sda=Pin(16))  # Use correct GPIOs for your setup
adc = ads1x15.ADS1115(i2c, 0x48)  # Default I2C address

# Read from channel 0
value = adc.read(0)
print("ADC Value:", value)

When I run this code, I get the following error.

>>> %Run -c $EDITOR_CONTENT

MPY: soft reboot
Traceback (most recent call last):
  File "<stdin>", line 8, in <module>
  File "ads1x15.py", line 162, in read
  File "ads1x15.py", line 139, in _write_register
OSError: [Errno 5] EIO

This is strange because when I try to detect the i2c devices, using the code below, a device is detected in 0x48, as it should be.

# I2C Scanner MicroPython
from machine import Pin, SoftI2C

# You can choose any other combination of I2C pins
i2c = SoftI2C(scl=Pin(17), sda=Pin(16))

print('I2C SCANNER')
devices = i2c.scan()

if len(devices) == 0:
  print("No i2c device !")
else:
  print('i2c devices found:', len(devices))

  for device in devices:
    print("I2C hexadecimal address: ", hex(device))

I have multiple ADS1115 modules with me, so I tried with a couple of them and I still keep getting the same error. What might be causing this issue?

[robert-hh]

Error EIO is a communication error. The device is not found. The wiring looks OK, and the ADS1115 board has pull-up resistors. What is the result of I2c.scan(), once the I2C object is created. The ADDR pin of the ADS1115 is open. So it might be high, resulting in an address of 0x49.

[chamathkv]

Hi @robert-hh

You're right, using SoftI2C worked fine for me as well. The code was amended as shown below

from machine import I2C, Pin, SoftI2C
import ads1x15

i2c = SoftI2C(scl=Pin(17), sda=Pin(16))
adc = ads1x15.ADS1115(i2c, 0x48)  # Default I2C address

# Read from channel 0
value = adc.read(0)
print("ADC Value:", value)

And I got an ADC value. May I know how I can use a different port please?

[robert-hh]

A different port means a different MCU hardware, like Teensy 4.x or ESP32. But maybe this bug gets fixed soon. Because it used to work with RP2.

[robert-hh]

I made an Issue from your report. Looks like a bug.

[chamathkv]

A different port means a different MCU hardware, like Teensy 4.x or ESP32. But maybe this bug gets fixed soon. Because it used to work with RP2.

Got it. Thanks for all your help.

[robert-hh]

Strange enough, running the same code with the same boards this morning hardware I2C works fine. That's worse than a simple bug.