I2C read does not work on Artik053

[tadziopazur]

I have some questions regarding I2C implementation on Artik.

1. Why does read fail to generate a correct I2C transaction? What can I do to fix it?
2. The i2c driver does not finish the transaction when there is a write of 1 (one) byte. Why?
   How are devices that do not have registers (i.e.: pcf8574) supposed to be handled?
3. The I2C signals driven by artik053 devkit rise slowly. Is it relevant to the other observed behavior?

Details follow.

First, the i2c_read did not work for me: artik failed to put a transaction onto the bus (not even START has been generated, just three stray SCL pulses -- please note SDA is high all the time). Scope diagram:

Write works somewhat better, in the sense that there are correct transactions (with an exception) issued onto the bus:

This is what my test suite looks like:

BTW artik devboard I2C output rises slowly, at about 200ns (at 400kHz bus clock) to reach TTL 1. I wonder if this is of any relevance (scope diagram attached):

[pmarcinkiew]

Please double check if your probe compensation is valid.

See Tektronix manual for reference:
https://neurophysics.ucsd.edu/Manuals/Tektronix/TDS%201000B%20and%20TDS%202000B%20Manual.pdf

[tadziopazur]

The probe is rated at 200MHz, 10MOhm, <12pF. I checked it at the 1kHz supplied by the scope, it looked good.
I think the signal (400kHz square waveform) is within the operating range of the scope (+probes).
Still I am not sure why these slopes rise so slowly, nor do I know if that affects the I2C communication.
It does not look like the communication is affected (at least not with Arduino Uno on the other side).

[rzr]

i2c worked for me on ARTIK055S (using IoT.js) I can share more details if it helps.

[rzr]

Mistake I was confused you're talking about I2C I think I used ADC.

[rzr]

Does i2ctool detect any item on bus ?

You need to rebase on it to use it:
#2439 (comment)