AN541

www.DataSheet4U.com AN541 Don Lekei NII Norsat International Inc. Using a PIC16C5X as a Smart I2C™ Peripheral Author: FIGURE 1: SCL I2C TIMING INTRODUCTION SDA PIC16C5X microcontrollers from Microchip are ideally suited for use as smart peripheral devices under the control of the main processors in systems, due to their low cost and high speed. They are capable of performing tasks which would simply overload a conventional microprocessor, or require considerable logic circuitry, at a cost competitive with lower mid-range PLDs. To minimize the engineering overhead of adding multiple controllers to a product, it is convenient for the auxiliary controllers to emulate standard I/O peripherals. A common interface found in existing products is the I2C bus. This efficient, two-wire, bi-directional interface allows the designer to connect multiple devices together, with the microprocessor able to send data to and receive data from any device on the bus. This interface is found on a variety of components, such as PLLs, DACs, video controllers, and EEPROMs. If a product already contains one or more I2C devices, it is simple to add a PIC16C5X emulating a compatible component. This application note describes the implementation of a standard slave device with multiple, bi-directional registers. A subset of the full I2C specification is supported, which can be controlled by the same software which would talk to a Microchip 24LCXX series EEPROM. tSH Start tCL tCH More Bits Stop Data...