Справочник Пользователя для Freescale Semiconductor Demonstration Board for Freescale MC9S12XHY256 Microcontroller DEMO9S12XHY256 DEMO9S12XHY256

Freescale Semiconductor

393

The inter-IC bus (IIC) is a two-wire, bidirectional serial bus that provides a simple, efficient method of data
exchange between devices. Being a two-wire device, the IIC bus minimizes the need for large numbers of
connections between devices, and eliminates the need for an address decoder.

This bus is suitable for applications requiring occasional communications over a short distance between a
number of devices. It also provides flexibility, allowing additional devices to be connected to the bus for
further expansion and system development.

The interface is designed to operate up to 100 kbps with maximum bus loading and timing. The device is
capable of operating at higher baud rates, up to a maximum of clock/20, with reduced bus loading. The
maximum communication length and the number of devices that can be connected are limited by a
maximum bus capacitance of 400 pF.

The IIC module has the following key features:

•

Compatible with I2C bus standard

•

Multi-master operation

•

Software programmable for one of 256 different serial clock frequencies

•

Software selectable acknowledge bit

•

Interrupt driven byte-by-byte data transfer

•

Arbitration lost interrupt with automatic mode switching from master to slave

•

Calling address identification interrupt

•

Start and stop signal generation/detection

•

Repeated start signal generation

V01.03

28 Jul 2006

- Update flow-chart of interrupt routine for 10-bit address

V01.04

17 Nov 2006

- Revise Table1-5

V01.05

14 Aug 2007

- Backward compatible for IBAD bit name