Cyclone® V Hard Processor System Technical Reference Manual

ID 683126
Date 8/28/2023
Public
Document Table of Contents

21.4.1. Feature Usage

The I2C controller can operate in standard mode (with data rates of up to 100 Kbps) or fast mode (with data rates less than or equal to 400 Kbps). Additionally, fast mode devices are downward compatible. For instance, fast mode devices can communicate with standard mode devices in 0 to 100 Kbps I2C bus system. However, standard mode devices are not upward compatible and should not be incorporated in a fast-mode I2C bus system as they cannot follow the higher transfer rate and therefore unpredictable states would occur. †

You can attach any I2C controller to an I2C-bus and every device can talk with any master, passing information back and forth. There needs to be at least one master (such as a microcontroller or DSP) on the bus and there can be multiple masters, which require them to arbitrate for ownership. Multiple masters and arbitration are explained later in this chapter. †