Iebus Communication Protocol; Overview; Table 13.4.1A Iebus Transfer Rates - Fujitsu F2MC-16LX MB90580 Series Hardware Manual

13.4 IEBus Communication Protocol

13.4.1 Overview

IEBus (Inter Equipment Bus) is a small-scale two-line serial bus interface intended to transfer data
between equipment and equipment.
• Communication method
Data are transferred by means of half duplex asynchronous communication.
• Multi-master method
All the units connected to the IEBus can transfer data to the other units.
• Multiaddress communication function (one unit can communicate to two or more units simultaneously)
Group communication: multiaddress communication to group units
Broadcasting communication: multiaddress communication to all units
• Three transfer rates can be selected:
IEBus internal clock
Mode
= 6MHz
0 approx. 3.9Kbps
1 approx. 17Kbps
2 approx. 26Kbps
• Access control: CSMA/CD (Carrier Sense Multiple Access with Collision Detection)
• The priority to occupy the IEBus:
(1) Multiaddress communication takes precedence over normal communication (communication
between one unit and another).
(2) The lower master address takes precedence over the higher address.
• Communication scale
Number of units: 50 max.
Cable length: 150m max. (when twisted pair cable with resistance less than 0.1 W/m is used)
loading Capacitance: 8000pF max. (between BUS- and BUS+) when IEBus internal clock is 6 MHz
Terminal resistance: 120 W.
Note:The system sacle depends on the IE Bus driver/receiver that is used.
MB90580 Series

Table 13.4.1a IEBus transfer rates

IEBus internal clock
= 6.29MHz
approx. 4.1 Kbps
approx. 18 Kbps
approx. 27Kbps
Note
7100pF max. (between BUS- and BUS+) when IEBus internal clock is 6.29MHz
13.4 IEBus Communication Protocol
Maximum number of transfer bytes
(bytes / frame)
16
32
128
Chapter 13: IE Bus 163