CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
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19.1.4 Communication address
With the IEBus, each unit is assigned a specific 12-bit address. This communication address consists of the
following identification numbers:
•
Higher 4 bits: Group number (number to identify the group to which each unit belongs)
•
Lower 8 bits: Unit number (number to identify each unit in a group)
19.1.5 Broadcasting communication
Normally, transmission or reception is performed between the master unit and its partner slave unit on a one-to-
one basis. During broadcasting communication, however, two or more slave units exist and the master unit executes
transmission to these slave units. Because plural slave units exist, the slave units do not return an acknowledge
signal during communication.
Whether broadcasting communication or normal communication is to be executed is selected by broadcasting bit
(for this bit, refer to
19.1.6 (2) Broadcasting bit
).
Broadcasting communication is classified into two types: group-unit broadcasting communication and all-unit
broadcasting communication. Group-unit broadcasting and all-unit broadcasting are identified by the value of the
slave address (for the slave address, refer to
19.1.6 (4) Slave address field
).
(1) Group-unit broadcasting communication
Broadcasting communication is performed to the units in a group identified by the group number indicated by
the higher 4 bits of the communication address.
(2) All-unit broadcasting communication
Broadcasting communication is performed to all the units, regardless of the value of the group number.