PD72042B_15 Datasheet, PDF (13/92 Pages) Renesas Technology Corp – LSI DEVICE FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL

µPD72042B
2.2.3 Communication Address
With the IEBus, each device is assigned a unique 12-bit communication address. The communication address
consists of the following parts:
High-order 4 bits : Group number (number identifying the group to which a device belongs)
Low-order 8 bits : Unit number (number identifying a device in a group)
2.2.4 Broadcast
In ordinary communication, transmission and reception are performed between one master unit and one associated
slave unit. Broadcast can also be done between one master unit and more than one slave unit. In this case master
unit transmits data to an arbitrary number of slave units. In this case, the slave units do not return on acknowledge
signal to the master unit.
Whether the communication to be performed is broadcast or ordinary communication is determined by the setting
of the broadcast bit. (For details of the broadcast bit, see (1) 2 in Section 2.3.)
There are two types of broadcast.
(1) Group broadcast
Broadcast is performed to the devices in a particular group. These devices all have the same group number,
as indicated by the high-order 4 bits of each communication address.
(2) General broadcast
Broadcast is performed to all devices, regardless of their group numbers.
These two types of broadcast are distinguished by the slave address. (For details of the slave address, see (3)
in Section 2.3.)
2.3 TRANSMISSION PROTOCOL
Fig. 2-1 shows the IEBus transmission signal format.
Communication data is transmitted as a sequence of signals called a communication frame. The transmission
speed and the maximum amount of data that can be transmitted in one communication frame depend on the
communication mode.
Data Sheet S13990EJ3V0DS
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