Dear AE team,
We are meeting an application issue of HDC1080, different pull up resistors of SDA/SCL will result of different result.
We tested the pull up resistor lower than 2.2Kohm, the communication is error with HDC1080.
When changed to 10Kohm, the communication is correct with HDC1080.
Also we have added an pull down capacitor 10pF or 22pF on SDA, and keep the 2.2Kohm pull up resistors on SDA/SDA, then the communication is correct.
You can check the attached figure for the connection between MCU(GPIO to simulate I2C) and HDC1080.
vcc=3.3V
Figure 1#: I2C communication error
Figure 2# work
Figure 3# work
My questions:
what is the pull up resistors value on the SDA/SCL between MCU and HDC1080?
how to calculate the value of these pull resistors? based on which theory?
Appreciated your comments.
Best Regards
Iven