Bus Pirate I2C Scanning and Device Communication

This experiment demonstrates how to use the Bus Pirate to scan for I2C devices and communicate with them.

1. Introduction to I2C and the Bus Pirate

The I2C (Inter-Integrated Circuit) protocol allows for simple, two-wire communication between a controller and one or more devices. The Bus Pirate can act as the controller to scan for devices and communicate with them directly over I2C.

2. Required Components

Bus Pirate (v3.6 or later)
I2C device (e.g., an I2C temperature sensor or EEPROM)
Connecting wires or breadboard
Computer with terminal software (like PuTTY or Tera Term)

3. Connecting the I2C Device

Wire the I2C device to the Bus Pirate as follows:

SDA (Data Line) on Bus Pirate to SDA on the I2C device
SCL (Clock Line) on Bus Pirate to SCL on the I2C device
Connect the GND and 3.3V power as required by your device

Open your terminal software, set the baud rate to 115200, and connect to the Bus Pirate’s serial port.

4. Entering I2C Mode on the Bus Pirate

After connecting to the Bus Pirate, set it to I2C mode:

m 4

Activate power and pull-up resistors:

P   (Turn on power supplies)
p   (Enable pull-up resistors)

Now the Bus Pirate is ready to scan for and communicate with I2C devices.

5. Scanning for I2C Devices

To identify devices on the I2C bus, use the Bus Pirate’s scanning command:

(1)

This command will scan the bus and display any detected device addresses, helping you confirm that your I2C device is connected and responsive.

6. Communicating with an I2C Device

Once you've identified the address, use the following syntax to send and receive data. Replace 0x50 with your device's actual address.

Writing to the Device: For example, to write data 0xAB to register 0x01:
```
[0x50 0x01 0xAB]
```
Reading from the Device: To read from register 0x01:
```
[0x50 0x01 [ 0x51 r]
```
In this command, [ starts reading mode, r reads one byte, and ] closes communication.

Refer to your device’s datasheet to understand which registers to access.

7. Advanced Commands

Some I2C devices may require additional steps or configurations. The Bus Pirate supports various commands, such as:

(2) - Read raw ADC
(3) - Continuous ADC
(4) - Sniff traffic on the I2C bus

Experiment with these commands for further insight into I2C communication.

8. Conclusion

This experiment provides the basics of using the Bus Pirate for I2C communication. From scanning devices to reading and writing data, the Bus Pirate offers extensive functionality for working with I2C components.