i2c device Wiring on Expansion Board & WiPy 3.0

[svonbentzel]

New need help with Pycom Expansion Board and WiPy 3.0

Hello together, I am new in this topic. ;-)

i want to connect a i2c device on my PyCom Expansion Board with a WiPy 3.0

i have search in documentation, but I can't find the correct wiring.
Can me anyone tell the correct Pinout for SDA/SCL please?

result of i2c Scan is noting actually

[svonbentzel]

@eric-waai

Yes it was a typo

I have 3 i2c devices

[Eric Waai]

@svonbentzel said in i2c device Wiring on Expansion Board & WiPy 3.0:

PIN 9 SDA --> Device 1 --> Device 2 --> Device 4
PIN 10 SCL --> Device 1 --> Device 2 --> Device 3

this makes no sense. but i think you meant
PIN 10 SCL --> Device 1 --> Device 2 --> Device 4

note that I2C is not designed for data transfer on long cable lengths
. it can give you weird transmission problems if the distances between devices add up

[alidaf]

As long as each device has a unique address. I2C relies on the device address to deliver or retrieve data. Some devices have a jumper that allows multiple addresses but most are fixed. Otherwise you will need separate SDA and SCL lines.

[svonbentzel]

i have a new question:

can I connect several i2c devices to a BUS / pin? So in a row?

PIN VCC --> Device 1 --> Device 2 --> Device 3
PIN GND --> Device 1 --> Device 2 --> Device 3
PIN 9 SDA --> Device 1 --> Device 2 --> Device 3
PIN 10 SCL --> Device 1 --> Device 2 --> Device 3

Sorry i got a typo in device 4 instead 3

[svonbentzel]

oh many many thanks ! ;-)
I try and will report!

[alidaf]

@svonbentzel The documentation is hard to find but try here:

https://docs.pycom.io/firmwareapi/pycom/machine/i2c

The default pins are P9 for SDA and P10 for SCL. Most pins can be configured though.