Chapter 18: Problem 8
True or false. In I2C devices, the 8-bit data is followed by an ACK/NACK.
Short Answer
Expert verified
True, in I2C devices, the 8-bit data is followed by an ACK/NACK bit.
Step by step solution
01
Understand the I2C Protocol
The I2C protocol is a synchronous, multi-master, multi-slave, packet switched, single-ended, serial communication bus. It has been widely used for attaching lower-speed peripheral ICs to processors and microcontrollers. In I2C communication, data is transferred in messages that are broken into a sequence of bytes.
02
Analyze Data Transfer Sequence in I2C
When data is being transferred via I2C, each byte of data sent by the transmitter is followed by an acknowledgment bit. After each 8-bit data byte, the receiver sends an ACK (acknowledge) bit if it successfully received the byte, or a NACK (not acknowledge) bit if it did not.
03
Determine the Truth Value
Based on the I2C protocol specifications, it is true that in I2C devices, every 8-bit data byte is followed by an ACK/NACK bit depending on whether the data was correctly received.
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Data Transfer in I2C
Understanding the intricacies of data transfer in I2C is crucial for leveraging this communication protocol effectively. I2C facilitates the movement of data between integrated circuits via a serial communication bus.
During transmission, data is sent in a precise format: a start condition is followed by the address of the destination device, and the data itself. After the transmission of each 8-bit chunk of data, the communication protocol requires a return signal from the receiving device. This signal can either be an acknowledge (ACK) or not-acknowledge (NACK) bit, acting as a response to the sender about the status of the received data.
The structured nature of data transfer within I2C ensures that even in a busy electronic environment, with multiple devices communicating, data can be sent and received with high integrity and minimal confusion.
During transmission, data is sent in a precise format: a start condition is followed by the address of the destination device, and the data itself. After the transmission of each 8-bit chunk of data, the communication protocol requires a return signal from the receiving device. This signal can either be an acknowledge (ACK) or not-acknowledge (NACK) bit, acting as a response to the sender about the status of the received data.
The structured nature of data transfer within I2C ensures that even in a busy electronic environment, with multiple devices communicating, data can be sent and received with high integrity and minimal confusion.
ACK/NACK in I2C
The acknowledgement (ACK) and not-acknowledgement (NACK) signals are foundational to the I2C protocol. They play a significant role in reinforcing the protocol's robust nature.
After each 8-bit data byte is transmitted, the receiving device sends back an ACK bit if the byte was correctly received, or a NACK bit if an error was detected or if the device is not ready for or capable of further communication. This bidirectional feedback mechanism helps in preventing data loss and ensures that the transmitting device is aware of the receiver's state—forming the basis for an error-checking procedure. It is a pivotal aspect of I2C, as it determines whether the communication is to continue or be halted for troubleshooting.
After each 8-bit data byte is transmitted, the receiving device sends back an ACK bit if the byte was correctly received, or a NACK bit if an error was detected or if the device is not ready for or capable of further communication. This bidirectional feedback mechanism helps in preventing data loss and ensures that the transmitting device is aware of the receiver's state—forming the basis for an error-checking procedure. It is a pivotal aspect of I2C, as it determines whether the communication is to continue or be halted for troubleshooting.
Serial Communication Bus
The term 'serial communication bus' refers to a system of data transfer that allows multiple devices to communicate over a single or a few wires in sequence, or serially.
Unlike parallel communication, where data is transferred over multiple lines simultaneously, serial communication sends data one bit at a time. I2C is an example of such a bus, utilizing two wires: SDA (Serial Data Line) and SCL (Serial Clock Line). These lines are responsible for data transmission and synchronization between devices, respectively. The advantage of a serial communication bus like I2C over parallel communication is its simplicity and efficiency, reducing the complexity in wiring and the potential for signal interference—making it highly suitable for short-distance communications within a device.
Unlike parallel communication, where data is transferred over multiple lines simultaneously, serial communication sends data one bit at a time. I2C is an example of such a bus, utilizing two wires: SDA (Serial Data Line) and SCL (Serial Clock Line). These lines are responsible for data transmission and synchronization between devices, respectively. The advantage of a serial communication bus like I2C over parallel communication is its simplicity and efficiency, reducing the complexity in wiring and the potential for signal interference—making it highly suitable for short-distance communications within a device.
I2C Protocol Specifications
Diving into the I2C protocol specifications reveals a structured and scalable method designed for inter-IC communications. This protocol encompasses a set of rules and electrical specifications that ensure various devices can communicate smoothly.
An I2C system must abide by the protocol's speed classes, which range from Standard-mode (100 kbit/s) to Ultra-fast-mode (5 Mbit/s). Each device connected to the I2C bus is assigned a unique address, facilitating targeted communication. Furthermore, I2C supports an arbitration process that allows multiple masters to attempt to take control of the bus without causing conflict. These and other specifications, such as voltage levels and timing requirements, enable a consistent and reliable communication framework that can be implemented across a wide array of electronic components and systems.
An I2C system must abide by the protocol's speed classes, which range from Standard-mode (100 kbit/s) to Ultra-fast-mode (5 Mbit/s). Each device connected to the I2C bus is assigned a unique address, facilitating targeted communication. Furthermore, I2C supports an arbitration process that allows multiple masters to attempt to take control of the bus without causing conflict. These and other specifications, such as voltage levels and timing requirements, enable a consistent and reliable communication framework that can be implemented across a wide array of electronic components and systems.
