"Does attaching a slave device to the SDA and SCL ports automatically pull them up ?"Are I2C internal pullups automatically enabled ?
"Did I miss anything?"Yes, the OP is software guy and anyhing hardware related is TMI."Without wishing to cause offence, you've been told multiple times how to do this but you keep asking the same question, I am beginning to think you are behaving like a troll"63 posts to ask about a pullup resistor ?Really ?And we're not out of the woods yet...
QuoteQuoteand make sure that SDA is pulled up, and that SCL is also pulled up I also understand to treat SDA and SCA pull ups differently though how do I wire this pull up ?
and make sure that SDA is pulled up, and that SCL is also pulled up
Attaching a slave device pulls them up if - and only if - there are pullups on the slave device module. It has nothing to do with the microcontroller.The "wire" library chooses to enable the internal pullups which may however in themselves be insufficient,.
One of my slave boards is at 3.3V and the other is at 5V. Though the Feather Huzzah and ESP32 are at 3.3V.
No need to draw a picture, something along the lines of " one end of a 4.7k resistor into the merged SDA leads and the other end into (VCC or +3.3V or 5V). And therein lies a rub. One of my slave boards is at 3.3V and the other is at 5V. Though the Feather Huzzah and ESP32 are at 3.3V. After much tired hammering at this, I have realized that I might need to go somewhere else to try and get help.As shown by Paul__B, there is more to this than just hooking wires. There are a lot of "ifs" here.