Why am I only receiving the first address byte? (I2C Protocol)

Question

Expecting the slave to ACKnowledge and return data, but it does not. This is my protocol. This is my Datasheet

The datasheet mentions \"The slave will answer by sending

Answer 1

For I2C, it is very important to have pull-up resistors on both SDA and SCL pins. If these are not present, the bus will always read low or floating voltage. I do not know the AVR hardware enough to know how it would behave, but I would expect the "// check if the start condition was successfully transmitted" to fail if this is the case.

In general when developing for hardware like this, I do recommend to have a logic analyzer. It can help when you are blind to what the hardware bus actually does.

An example of such device is https://www.saleae.com/ ,but multiple vendors and/or open projects exists.