I2C at expansion board

[Lopyusr]

Hello there,

im a bit confused about setting up the I2C Bus.
I can use my sensor at Pin9 and Pin10 without any problems, but i cant manage to set up any other Pins for I2C. I read that this should be working but i couldnt get it done by now. I use FW 1.8.6

The Sensor seems not to exist when i connect it to any other Pins. (i.e. Pins 11 and 12)

Actually i use a class to control my sensor

import time
import pycom
from machine import I2C

class DHT12():

def __init__(self,pinSDA='P9',pinSCL='P10',bd=100000):
    self.i2c = I2C(2, pins=(pinSDA,pinSCL)) 
    self.i2c.init(I2C.MASTER, baudrate=bd)
    self.addr = self.i2c.scan()  

When i change pinSDA to P19 and pinSCL to P20
i get I2C bus error and a strange behaviour
Bild Link)

Thanks in advance for any help on this topic.

[ledbelly2142]

@lopyusr I apologize, I misunderstood. I provided too much info on something not your issue.

I'm assuming you are using this driver and example: HERE

And documentation HERE

[Lopyusr]

@ledbelly2142 Im using a DHT12 temperature and humidity sensor. I dont get the point with that battery reading code. I just wonder why it is working on the Pins 9 and 10 but not at any onthers :/ Yfyi i use the Expansion board also. Best regards for your help.

[ledbelly2142]

This post is deleted!

[Lopyusr]

@ledbelly2142 It all works fine until i try changing the Pins i cant figure out what im doing wrong at this point :/

[Lopyusr]

Im building a driver file. So im initing the sensor at given ports.

When i try
i2c = I2C(0,mode=I2C.MASTER,pins=('P9','P10'),baudrate=1000000)

i get the following result

i2c = I2C(0,mode=I2C.MASTER,pins=('P20','P19'),baudrate=1000000)

results in

when i try i2c.scan() at this config i dont get a result.

[Xykon]

@lopyusr said in I2C at expansion board:

self.i2c = I2C(2, pins=(pinSDA,pinSCL))
self.i2c.init(I2C.MASTER, baudrate=bd)

Please try the following instread:

self.i2c = I2C(2, mode=I2C.MASTER, pins=(pinSDA,pinSCL),baudrate=bd)
self.i2c.init(I2C.MASTER, baudrate=bd)

Please also remember that I2C bus nr. 2 is emulated in software while I2C bus 0 and 1 are hardware I2C ports, so you might not get reliable communication at this speed when using bus nr. 2

[ledbelly2142]

@lopyusr Try this before you class or def

i2c = I2C(0, I2C.MASTER, baudrate=100000, pins=('P8','P9'))

What are you init -ing?

Or maybe try this

def __init__(self, i2c, address=0x29): # where0x29 is your device I2C address
        self.i2c = i2c
        self._address = address