This document describes the implementation of the Serial Camera Control Bus (SCCB) interface using software and general-purpose pins on Blackfin® processors. Because of its architecture and video processing capabilities, Blackfin processors are well-suited to interface with video devices. Many of these video devices in the signal chain must be configured by an I2C®- compatible hardware interface.
This Engineer-to-Engineer Note (EE-204) details how to implement the Serial Camera Control Bus (SCCB) interface using software and general-purpose pins on Blackfin processors. It provides a solution for Blackfin derivatives that lack a built-in two-wire interface (TWI) for configuring video devices, allowing the processor to act as an I2C master.
The software is designed specifically for the ADSP-BF533 and ADSP-BF561 processors.
The interface uses two general-purpose pins, PFO for the clock line and PF1 for data transmission and reception.
The clock rate is determined by the interrupt interval of timer0, which generates an interrupt after its counter has expired.