Functions; Iebus Communication Protocol - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
22.7

Functions

22.7.1

IEBus communication protocol

Caution
Caution
R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
The communication protocol of the IEBus is as follows.
(1) Multi-task mode
All the units connected to the IEBus can transfer data to the other units.
(2) Broadcast communication
Communication between one unit and multiple units can be performed as follows.
• Group broadcast communication: Broadcast communication to group units
• All-unit broadcast communication: Broadcast communication to all units
(3) Effective transmission speed
The effective transfer rate is in communication mode 1 or communication mode 2.
(This product does not support mode 0 for the effective transfer rate.)
• Communication mode 1: Approx. 18 kbps
• Communication mode 2: Approx. 27 kbps
Different modes (communication mode 1, communication mode 2) 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 maximum
• Cable length: 150 m maximum (when twisted pair cable is used)
The communication scale in an actual system differs depending on the
characteristics of the cables, etc., constituting the IEBus driver/receiver and
IEBus.
22. IEBus Controller
22-111