C Bus Interface Unit; Overview; Signal Description; Functional Description - Intel PXA255 Developer's Manual

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I

C Bus Interface Unit

This chapter describes the Inter-Integrated Circuit (I2C) bus interface unit, including the operation
modes and setup for the PXA255 processor.
9.1

Overview

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The I C bus was created by the Phillips Corporation and is a serial bus with a two-pin interface.
The SDA data pin is used for input and output functions and the SCL clock pin is used to control
and reference the I
that resides on the I
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The I C unit enables the processor to communicate with I
system management functions. The I
and reliability information concerning the processor subsystem to an external device.
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The I C unit is a peripheral device that resides on the processor internal bus. Data is transmitted to
and received from the I
through a set of memory-mapped registers. Refer to The I
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on I C bus operation.
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Note: The I C unit does not support the hardware general call, 10-bit addressing, or CBUS compatibility.
9.2

Signal Description

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The I C unit signals are SDA and SCL.
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Table 9-1. I C Signal Description
Signal Name
SDA
SCL
9.3

Functional Description

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The I C bus defines a serial protocol for passing information between agents on the I
two pin interface that consists of a Serial Data/Address (SDA) line and a Serial Clock Line (SCL).
Each device on the I
or as a receiver in master or slave mode.
Intel® PXA255 Processor Developer's Manual
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C bus. The I C unit allows the processor to serve as a master and slave device
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C bus.
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C bus requires a minimum amount of hardware to relay status
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C bus via a buffered interface. Control and status information is relayed
Table 9-1
Input/Output
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Bidirectional I C Serial Data/Address signal
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Bidirectional I C Serial Clock Line signal
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C bus is recognized by a unique 7-bit address and can operate as a transmitter
Table 9-2
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C peripherals and microcontrollers for
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C-Bus Specification for complete details
describes each signal's function.
Description
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lists the I C operation modes.
9
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C bus using a
9-1