I2C OSerrors: 5, 116, 16 problem with interfacing to ADS1115

[tomrogue]

Hey there,

So I've read all the posts on this forum regarding I2C and OSerrors:5, 116 and 16 with no real insight into why I might be experiencing the issues I am.

Basically, I'll usually be able to write to the ADC with something like:
i2c.mem_write(data, address, config_reg, addr_size=16)
and no exceptions will be thrown. Then, when I try to read a conversion via:
i2c.mem_read(2 , address, convert_reg, addr_size=16)
I'll get an OSError: 5, followed by 116's to infinity (should I try the same operation repeatedly).
I have also tried to use i2c.send(data, address) and i2c.recv(data, address) to accomplish what mem_write/mem_read would do, and in this case I get OSerror: 16 where the ADC or i2c bus stop communication and
i2c.scan() returns : []

So my question is:
Am I missing something in the I2C functions themselves, or is this likely pilot error on my part with not understanding something about my ADC chip (it seems really straight forward). Anyhoo...thanks in advance for any responses

[pythoncoder]

If i2c.scan() returns an empty list your hardware isn't being detected. I'd double check the electrical connections.

[blmorris]

I suspect that it isn't an electrical issue, or the mem_write call would have failed because the pyboard would not have received an ACK on each transmitted byte. It is possible that the mem_read call produces an error which causes the I2C bus to hang, so that all subsequent I2S calls generate errors as well. If I am correct in this, reinitializing the I2C bus (i2c.deinit(), i2c.init()) should get the scan call to work.
Are you sure that you need to use 'addr_size=16'? I'm not familiar with the ADS1115, but typically you only need 16-bit addresses for I2C devices with more than 256 registers (like an external memory or a device that uses I2C to load a program to boot up), and sometimes even then you don't need it.

-Bryan

Edit- the ADS1115 is a 16-bit ADC; I would guess that there are only a handful of configuration registers and that addr_size=16 isn't correct.