- Wed Sep 02, 2015 9:21 pm
#27673
Given that there are internal pull-resistors that can be enabled inside ESP8266, is it necessary to place pull-up resistors for I2C pins? Am I right that the i2c pins are GPIO 0 (SCL) and GPIO 2 (SDA)? By the way, is the SMING i2c library based on Arduino?
- Thu Sep 03, 2015 10:43 am
#27718
The internal pullups are "weak pullups" (probably around 47K or 100K), which is not enough for proper I2C Bus.
The best is to add some external ones, around 4K7.
The best is to add some external ones, around 4K7.
- Thu Sep 03, 2015 12:58 pm
#27729
I've tried DS18B20 and DHT11 sensors on ESP8266, and in both cases I needed to add 4.7k pullups, as Martin suggests. I think the pullup is part of the 1-wire and I2C standards, and some devices can even draw power from their data line ("parasitic" power).
And yes, alot of the Sming libraries come from Arduino.
And yes, alot of the Sming libraries come from Arduino.
