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jamesbowman / i2cdriver

I2CDriver open source tools
https://i2cdriver.com/
BSD 3-Clause "New" or "Revised" License
187 stars 57 forks source link

Bus arbitration #54

Closed limi97 closed 4 years ago

limi97 commented 4 years ago

Can you tell me about anything I need to do specifically to handle bus arbitration? What is supported? If I do the start command the arbitration bit is always set. How can I change this?

jamesbowman commented 4 years ago

image

This bit should definitely be zero. Being set suggests that either SCL or SDA is tied low. As a first test, I suggest you:

  1. remove power from I2CDriver
  2. remove all I2C peripherals from I2CDriver
  3. apply power to I2CDriver

And check if the start still leaves ARB high. If it does, the I2CDriver has a hardware fault, and I can replace it. If not, there is a problem with the I2C peripheral not releasing the bus.

limi97 commented 4 years ago

I tested this. The bit is zero if there is no peripheral connected to the driver. But if I connect a peripheral the bit goes one. I connected several options.

jamesbowman commented 4 years ago

Aha, thanks. On the software side, are you using the C library, Python, or something else?

jamesbowman commented 4 years ago

Also (sorry to have to ask this, but it has happened before) have you checked your hookup that SDA and SCL re not swapped? SCL is yellow, SDA is blue.

limi97 commented 4 years ago

Yes I have it the right way. Actually now it works. I did again what you described and now it works perfectly fine.

limi97 commented 4 years ago

Thanks for your help