robtillaart:
do you have pull up resistors?
for I2C you need typically 4K7 or with longer wires 2K2 (or lower) resistor between the SCL/DTA and +5V
Think that will also be true for softI2C
Yes, I have pull ups, but I used 10K, but also slow speed communication. I'll try test it with 4K7.
Northof49:
Is a breadboard and typical 6" long breadboard wires suitable for testing i2c devices?
Using of breadboard should be ok in my opinion. And wires I use as short as possible, not typical 6"
Grumpy_Mike:
I cannot use HW I2C (just because I use breadboard).
No that doesn't follow at all.
If there is something stopping you using hardware I2C then the same thing also stops you using software I2C.
What is it about your bread board that makes you think you can't use the hardware pins?
I cannot use HW I2C beacuse it is not possible to pin it into breadboard, because of arduino mini pro pins for I2C.
Thank you all