MC912D60ACPVE8 Datasheet, PDF (289/460 Pages) Freescale Semiconductor, Inc – MC68HC912D60A MC68HC912D60C MC68HC912D60P Technical Data

Technical Data — MC68HC912D60A
Section 16. Freescale Interconnect Bus
16.1 Contents
16.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
16.3 Push-pull sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
16.4 Biphase coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
16.5 Message validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
16.6 Interfacing to MI Bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
16.7 MI Bus clock rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
16.8 SCI0/MI Bus registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
16.2 Introduction
The Freescale 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 data transfer bit rate 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⁾
The MI Bus uses a push-pull sequence to transfer data. The master
device, which in this case is the MC68HC912D60A, sends a push field to
the slave devices connected to the bus. The push field contains data plus
an address that is recognized by one of the slaves. The slave addressed
returns data which the master pulls from the MI Bus over the same wire.
Specific details of the message format are covered later in this section.
The MCU (master) can take the bus at any time, with a start bit that
1. Related information on Freescale’s MI Bus is contained in the following Freescale publications:
EB409/D — The MI Bus and Product family for Multiplexing Systems
AN475/D — Single Wire MI Bus Controlling Stepper Motors
BR477/D — Smart Mover – Stepper Motors with Integrated Serial Bus Controller
MC68HC912D60A — Rev. 3.1
Freescale Semiconductor
Freescale Interconnect Bus
Technical Data
289