SparkFun Logic Level Converter - Bi-Directional

Other Miscellaneous
1

Hi there,

  1. If I’m to use pull-up resistors in both sides (3.3v and 5v sides) of the I2C line, I should consider a level shifting and or else disable Atmel328p input pull-ups of I2C lines and use without pull-up resistors and level shifting?

  2. Are the pull-up resistors enabled by default for I2C ports of Atmel328p?

  3. As a best design practice, should I always use pull-up resistors with a level shifting in I2C lines?

2

1- BOB-12009 has 10K pullups built in, those should be sufficient for I2C on their own in most cases.

2- ATmega Internal pullups are disabled when using I2C, external pullups are needed.

3- Pullup resistors are REQUIRED for the I2C bus to work, you need them on both sides of your level shifter but since BOB-12009 has them built in, you’re covered. :slight_smile: