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User’s Manual U12790EJ2V0UD
CHAPTER 17 IEBus CONTROLLER (
PD178096A, 178098A, 178F098 ONLY)
The
PD178098A Subseries (PD178096A, 178098A, 178F098) incorporates an IEBus controller.
IEBus (Inter Equipment Bus) is a small-scale digital data transfer system that transfers data between units. To implement
IEBus by using the
PD178098A Subseries, an external IEBus driver and receiver are necessary because they are not provided.
The internal IEBus controller of the
PD178098A Subseries is of negative logic.
17.1 IEBus Controller Functions
17.1.1 Communication protocol of IEBus
The communication protocol of the IEBus is as follows.
(1) Multitask mode
All the units connected to the IEBus can transfer data to the other units.
(2) Broadcast communication function
Communication between one unit and multiple units can be performed as follows.
Group-unit broadcast communication:
Broadcast communication to group units
All-unit broadcast communication:
Broadcast communication to all units
(3) Effective transfer rate
The effective transfer rate is in mode 1 (the
PD178098A Subseries does not support modes 0 and 2 for the effective
transfer rate).
Mode 1: Approx. 18 Kbps (when fX = 6.3 MHz)
Caution Different modes must not be mixed on one IEBus.
(4) Communication mode
Data transfer is executed in half-duplex asynchronous communication mode.
(5) Access control: CSMA/CD (Carrier Sense Multiple Access with Collision Detection)
The priority of the IEBus is as follows.
<1> Broadcast communication takes precedence over individual communication (communication from one unit to
another).
<2> The lower master address takes precedence.
(6) Communication scale
The communication scale of IEBus is as follows.
Number of units: 50 MAX.
Cable length:
150 m MAX. (when twisted pair cable is used)
Caution The communication scale in an actual system differs depending on the characteristics of the cables,
etc., constituting the IEBus driver/receiver and IEBus.