Tagged Questions

22
votes
4answers
3k views

\$I^2C\$ 3.3 to 5.0 V conversion

I'm trying to interface a 3.3V \$I^2C\$ device to a 5V Arduino. I don't have any problem with SCL line. I can use a simple voltage divider but I have an issue with the SDA line as this is ...
6
votes
2answers
3k views

How do I get an Arduino (5 V) and MPR121 (3.3 V) to talk?

I have the Sparkfun MPR121 I2C Capacitive touch sensor breakout board I have read that it uses 3.3 V, I know that I can't just connect up the 3.3 V power supply output from the Arduino as the ...
0
votes
2answers
53 views

Strange I2C behavior: sometime it works, some time it doesn't

I am using Arduino Ethernet with PoE and Arduino Uno boards. In recent days I implemented a working I2C bus by using the Wire library and all it seemed almost to ...
1
vote
1answer
335 views

communication between 2 arduino crash when external power supply is plugged

i have one arduino mega that communicates with one arduino leonardo. the leonardo controls some motors (mega tell to the leonardo how many step to do... leonardo is a coprocessor for the motor in ...