Freescale Semiconductor, Inc.
Technical Data — MC68HC11P2
Section 6. Motorola Interconnect Bus (MI BUS)
6.1 Contents
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
Push-pull sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111
The push field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
The pull field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
Biphase coding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
Message validation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
Interfacing to MI BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
MI BUS clock rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
6.10 SCI/MI BUS2 registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
6.11 SCI/MI BUS3 registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
6.2 Introduction
The Motorola Interconnect Bus (MI BUS) is a serial communications
protocol which supports distributed real-time control efficiently and with
a high degree of noise immunity, at a typical bit rate for the data transfer
of 20kHz. The MI BUS is suitable for medium speed networks requiring
very low cost multiplex wiring; only one wire is required to connect to
slave devices.(1)
1. Related information on Motorola’s MI BUS is contained in the following Motorola publications:
MC68HC11P2 — Rev 1.0
Technical Data
Motorola Interconnect Bus (MI BUS)
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