MC68HC05L28 Datasheet, PDF (81/156 Pages) Motorola, Inc – Flexible general-purpose microcomputer

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I²C-BUS
I²C-bus is a two-wire, bidirectional serial bus that provides a simple, efficient way to exchange data
between devices. Being a two-wire device, the I²C-bus minimizes the need for large numbers of
connections between devices, and eliminates the need for an address decoder.
The bus is suitable for applications involving frequent communications between a number of
devices over short distances. The number of devices connected to the I²C-bus is limited only by a
maximum bus capacitance of 400pF; it has a maximum data rate of 100 kbits per second.
The I²C-bus system is a true multi-master bus including collision detection and arbitration to
prevent data corruption if two or more masters attempt to control the bus simultaneously. This
feature provides the capability for complex applications with multiprocessor control. It may also be
used for rapid testing and alignment of end products via external connections to an assembly line
computer.
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The I²C-bus function is enabled by the MEN bit in the I²C-bus control register (MCR).
8.1 I²C-bus features
• Multi-master operation
• Software-programmable for one of 32 different serial clock frequencies
• Software-selectable acknowledge bit
• Interrupt-driven, byte-by-byte data transfer
• Arbitration-lost-driven interrupt with automatic switching from master to slave mode
• Calling address identification interrupt
• Generates/detects the START or STOP signal
• Repeated START signal generation
• Generates/recognizes the acknowledge bit
• Bus busy detection
MC68HC05L28
I²C-BUS
TPG
MOTOROLA
8-1