I2C pull up resistors implemented twice

Projects General Guidance
1

Hello, I have a question regarding pull ups for I2C:

  1. My BMP180 in GY-68 board has 4.7k ohm pull ups for both SCL and SDA lines. While using Wire library I noticed that pull ups present in ATmega are also activated.

Standalone BMP180 works with my Leonardo, but after connecting it with other peripherals, something caused a serious freeze. May this double set of pull ups have influenced the malfunction?

  1. If I connect another I2C device like RTC DS1307 also equipped with its own pull up set of 2 x 3.3 k ohm.
    Is it possible that it - together with BMP180 (with another resistors) might not work properly?
2

yes as the resistors are in parallel the resulting value will even be smaller.

3

robtillaart:
yes as the resistors are in parallel the resulting value will even be smaller.

Thank you. That's an answer for 2.
The result is 1938 ohm - provided I disable ATmega built-in pull ups. Is that value acceptable?