AN 502: Implementing SMBus Controller in Altera MAX Series

ID 683635
Date 9/22/2014

1.1. Using a MAX II Device as an SMBus Controller

The detailed description of the implementation is based on the MAX II devices. This application can also be implemented in MAX V and MAX 10 devices.

You can implement this design using an EPM1270. The design source code is compiled and programmed into the MAX II devices. Host interfacing ports and SMBus lines are mapped on convenient I/O pins.

The MAX II device is a low cost, low power device. SMBus specification defines two classes of electrical characteristics: low power and high power. Implementing an SMBus controller in a MAX II device with the SMBus operating at low power is a desirable solution in any low power consumption application.

The MAX II device acts as a bridge between a host (for example, microcontroller or microprocessor) and the SMBus. The controller incorporates a host interface and an SMBus interface with the control signals coming from the former to the latter. The designed controller is capable of functioning as a master or a slave.

The SMBus controller sits between a generic microcontroller bus (with address, data, and control signals) and the SMBus. It presents itself as a peripheral to the microcontroller and as an SMBus device (Master or Slave) on the SMBus.

Figure 1. SMBus Block Diagram