# I2C

## Communication speed

* Normal
  * Fast
* High-speed

## Basic features

* Two-wire communication
* Half-duplex
  * Bidirectional communication (only one direction at a time)
* Multi-Master/Slave
* Clock stretching
  * Slave devices can hold the clock line (SCL) to allow more time for processing data
* Addressing
* Pull-up resistors
* Arbitration
  * Ensure data integrity when multiple masters attempting to use the bus simultaneously
    * Detect & resolve conflicts
    * Ensure data integrity
* ACK/NACK (acknowledge / not acknowledge)

## I2C implementation spec-sheet

### From TI (Texas Instruments)

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### From NXP

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[I2C-bus specification and user manual](https://www.nxp.com/docs/en/user-guide/UM10204.pdf)
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## I2C primers & use-full resources

### I2C Primer

A very nice primer that explains how the I2C protocol works and some special considerations that we should take work working with it. On the surface it seems like a very simple 2 wire protocol but some features such as multi-master/slave, clock stretching, etc. (& maybe error detection/correction?) makes implementation not as straightforward as it seems.

{% embed url="<https://www.i2c-bus.org/i2c-primer>" %}

## Debugging I2C

### Waveform analysis

<https://www.ti.com/lit/an/slyt770/slyt770.pdf>