Contents
What is the ACK bit in I2C?
The ACK bit allows the receiver to communicate to the transmitter that the byte was successfully received and another byte may be sent. Before the receiver can send an ACK, the transmitter must release the SDA line.
What is I2C pull up?
Each I2C bus consists of two signals: SCL and SDA. Each signal line has a pull-up resistor on it, to restore the signal to high when no device is asserting it low. Notice the two pull-up resistors on the two communication lines.
When to use ACK and Nack in I2C?
You really should read the I2C specification here, but briefly, there are two different cases to consider for ACK/NACK: After sending the slave address: when the I2C master sends the address of the slave to talk to (including the read/write bit), a slave which recognizes its address sends an ACK.
What is the operation of the I2C bus?
The operation of the I2C bus is a read and write process between master and slave devices. There are mainly divided into 3 processes: Master device writes data to the slave device: The master device reads data from the slave device:
How does an I2C address match a slave address?
I2C Protocol starts with a start bit followed by the slave address (7 bit address + 1 bit for Read/Write). After sending the slave address Master releases the data bus (SDA line), put the line in high impedance state leaving it for slave to drive the line. If address matches the slave address, slave pull the line low for the ACK.
How does a slave device start an I2C transaction?
At any time a master device can start a transaction by pulling SDA low while SCL is high (a unique specific condition that other I2C devices recognise as the start of a master transmission). The slave device listens to the next 7 serial bits of the address to see if it matches its own address (each I2C must have a unique address).