I2C

Warning

We recommend to use Vicharak 6.1 kernel and latest Ubuntu 24.04 Noble Numbat , in order to support below overlays. Flash Image using this Documentation

sudo apt update
sudo apt reinstall linux-image-6.1.75-axon linux-headers-6.1.75-axon

Introduction

I2C is a multi-master, multi-slave, packet-switched, single-ended serial communication bus. It’s widely used for communication between microcontrollers and low-speed peripherals like sensors, EEPROMs, and real-time clocks. I2C operates with two lines:

SCL (Serial Clock Line): Provides the clock for the communication.

SDA (Serial Data Line): Transfers the data.

Axon has 4 I2C’s protocol on 30 Pins GPIO Header. Like, I2C1, I2C2, I2C5 and I2C7

Tip

To get more information on Axon GPIO Header.

Key features of I2C include:

Addressable Devices: Each device connected to the I2C bus has a unique 7- or 10-bit address.
Simplicity: Requires only two wires, which simplifies the layout.
Data Speeds: Operates at standard modes (100 kbps), fast modes (400 kbps), and high-speed modes (up to 3.4 Mbps).
Multi-master: Allows multiple masters to control the bus.

How to use GPIO Pins as I2C Protocol ?

Steps to follow for Configuration

Open a terminal window (Ctrl+Alt+T).
Run command sudo vicharak-config in it.
Select Overlays options in it by pressing enter key.

┌───────────────────────────────────┤ VICHARAK_CONFIG ├────────────────────────-───────────┐
│ Please select an option below:                                                           │
│                                                                                          │
│                                   System Maintanince                                     │
│                                       Hardware                                           │
│                                       Overlays                                           │
│                                     Connectivity                                         │
│                                   Advanced Options                                       │
│                                     User Settings                                        │
│                                     Localization                                         │
│                                         About                                            │
│                                                                                          │
│                      <Ok>                               <Cancel>                         │
│                                                                                          │
└──────────────────────────────────────────────────────────────────────────────────────────┘

You will see Warning Page, click on yes and select Manage Overlays options.

┌───────────────────────────────────┤ VICHARAK_CONFIG ├────────────────────────────────────┐
│ Configure Device Tree Overlay                                                            │
│                                                                                          │
│                                Manage overlays                                           │
│                                View overlay info                                         │
│                                Install 3rd party overlay                                 │
│                                Reset overlays                                            │
│                                                                                          │
│                                                                                          │
│                      <Ok>                               <Cancel>                         │
└──────────────────────────────────────────────────────────────────────────────────────────┘

Select overlays as per your requirement ( I2C1 / I2C2 / I2C5 / I2C7 ) by pressing spacebar on keyboard, then select Ok.

┌──────────────────────────────────┤ VICHARAK_CONFIG ├─────────────────────────────────────┐
│ Please select overlays:                                                                  │
│                                                                                          │
│  [ ] Enable DP connector-split mode Axon V0.3                                            │
│  [ ] Enable RasPi Camera V1.3 (OV5647) on CSI0 D0,1 dphy1 Axon V0.3                      │
│  [ ] Enable RasPi Camera V1.3 (OV5647) on CSI0 D2,3 dphy2 Axon V0.3                      │
│  [ ] Enable RasPi Camera V1.3 (OV5647) on CSI1 D0,1 dphy4 Axon V0.3                      │
│  [ ] Enable RasPi Camera V1.3 (OV5647) on CSI1 D2,3 dphy5 Axon V0.3                      │
│  [ ] Enable RasPi Camera V1.3 (OV5647) on dphy RX0 Axon V0.3                             │
│  [ ] Enable RasPi camera V1.3 (OV5647) on dphy RX1 Axon V0.3                             │
│  [*] Enable I2C1 on 30-Pin GPIO Header Axon V0.3                                         │
│  [ ] Enable I2C2 on 30-Pin GPIO Header Axon V0.3                                         │
│  [ ] Enable I2C5 on 30-Pin GPIO Header Axon V0.3                                         │
│  [ ] Enable I2C7 on 30-Pin GPIO Header Axon V0.3                                         │
│  [ ] Enable PWM0 on 30 Pin GPIO Header Axon V0.3                                         │
│  [ ] Enable PWM1_M0 on 30 Pin GPIO Header Axon V0.3                                      │
│  [ ] Enable PWM1_M0 on 30 Pin GPIO Header Axon V0.3                                      │
│  [ ] Enable UART1 on 30 Pin GPIO Header Axon V0.3                                        │
│  [ ] Enable UART4 on 30 Pin GPIO Header Axon V0.3                                        │
│  [ ] Enable UART6 on 30 Pin GPIO Header Axon V0.3                                        │
│  [ ] Enable Waveshare 4inch DSI LCD DPHY TX0 Axon V0.3                                   │
│  [ ] Enable Waveshare 4inch DSI LCD DPHY TX1 Axon V0.3                                   │
│                                                                                          │
│                                                                                          │
│                                                                                          │
│                                                                                          │
│                                                                                          │
│                     <Ok>                         <Cancel>                                │
│                                                                                          │
└──────────────────────────────────────────────────────────────────────────────────────────┘

To return back to terminal, press the Esc key until you exit from it.
In order to enable your configuration, Restart your computer or Run command sudo reboot in terminal.

How to interact with the generated I2C’s ?

Now, you can see I2C devices, which are accessible through device nodes such as:

ls -l /dev/i2c-*

If you have turned on I2C1 then you can get device like this /dev/i2c-1.

These i2c-* device nodes allow users to communicate with I2C peripherals such as sensors, EEPROMs, and other slave devices connected to the I2C bus.

Simple set/get I2C values

To use the i2cset, i2cget, and i2cdetect commands, you need to install the i2c-tools package. These tools are part of the i2c-utils package, which provides user-space tools for interacting with I2C devices via the Linux I2C subsystem.

sudo apt install i2c-tools

Identify I2C Buses and Devices:
- You can list available I2C buses using:
```
i2cdetect -l
```
- In i2c-*, where * represents an I2C bus number. For example, i2c-1 can communicate with multiple devices, each identified by a unique 7-bit or 10-bit address.
Detect I2C Devices on a Bus:
- To scan a particular bus for connected I2C devices, use:
```
sudo i2cdetect -y <bus_number>
```
- <bus_number>: The I2C bus number (like 1 from the previous command).
- For example, to scan bus 1:
```
sudo i2cdetect -y 1
```
- The output shows a grid with device addresses. Devices are listed by their 7-bit addresses.

GPIO

SPI