What is the use of SDA and SCL lines in I2C communication?
Line state table
Type | Inactive bus (N) | Idle (i) |
---|---|---|
Note | Free to claim arbitration | Bus claimed (controller) |
SDA | Passive pullup | Held low (controller) |
SCL | Passive pullup | Passive pullup |
How do I read I2C data?
A basic Master to slave read or write sequence for I2C follows the following order:
- Send the START bit (S).
- Send the slave address (ADDR).
- Send the Read(R)-1 / Write(W)-0 bit.
- Wait for/Send an acknowledge bit (A).
- Send/Receive the data byte (8 bits) (DATA).
- Expect/Send acknowledge bit (A).
- Send the STOP bit (P).
How do I find my I2C address?
- Find I2C address of your device. You can use i2cdetect or Explorer program to find current i2c address of your device.
- i2cdetect. Run: i2cdetect -y 1 [Press Enter] This program displays address in 7 bit format (multiply by 2 to get 8 bit format).
- Explorer Program. Navigate to appropriate folder. Run:
How do I read an I2C address?
A 7-bit I2C address includes a 7-bit slave address in the first 7 bits of a byte. The eighth bit (the bit in the Least Significant Bit position) is the read/write flag. A 0 in the eighth bit indicates a write and a 1 in the eighth bit signifies a read.
What is a 7 bit address?
In 7-bit addressing procedure, the slave address is transferred in the first byte after the Start condition. The first seven bits of the byte comprise the slave address. The eighth bit is the read/write flag where 0 indicates a write and 1 indicates a read. The slave address used should only be the top seven bits.
What is I2C arbitration?
Several I2C multi-masters can be connected to the same I2C bus and operate concurrently. By constantly monitoring SDA and SCL for start and stop conditions, they can determine whether the bus is currently idle or not. This process is called arbitration. …
How is the address of an I2C slave determined?
Basic I2C communication is using transfers of 8 bits or bytes. Each I2C slave device has a 7-bit address that needs to be unique on the bus. Some devices have fixed I2C address while others have few address lines which determine lower bits of the I2C address. This makes it very easy to have all I2C devices on the bus with unique I2C address.
What is the I2C bus and what does it do?
The I2C bus is a standard bidirectional interface that uses a controller, known as the master, to communicate with slave devices. A slave may not transmit data unless it has been addressed by the master. Each device on the I2C bus has a specific device address to differentiate between other devices that are on the same I2C bus.
How is a device identified in the I2C protocol?
Each I2C device (Master/slave) is identified by its 7-bit or 10-bit unique address known as device ID which is provided by device manufacturer only and can act as a transmitter or receiver at a time, depending on the configuration of it.
How many I2C addresses does the srf08 have?
The SRF08 has 36. Having sent the I2C address and the internal register address the master can now send the data byte (or bytes, it doesn’t have to be just one).