UPD72042BGT NEC [NEC], UPD72042BGT Datasheet - Page 11

• Manufacturer Part Number: UPD72042BGT
• Description: LSI DEVICE FOR Inter Equipment Bus (IEBus) PROTOCOL CONTROL
• Manufacturer: NEC [NEC]

2.2.3 Communication Address
consists of the following parts:
2.2.4 Broadcast
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.
of the broadcast bit. (For details of the broadcast bit, see (1) 2 in Section 2.3.)
(1) Group broadcast
(2) General broadcast
2.3 TRANSMISSION PROTOCOL
speed and the maximum amount of data that can be transmitted in one communication frame depend on the
communication mode.
With the IEBus, each device is assigned a unique 12-bit communication address. The communication address
High-order 4 bits : Group number (number identifying the group to which a device belongs)
Low-order 8 bits
In ordinary communication, transmission and reception are performed between one master unit and one associated
Whether the communication to be performed is broadcast or ordinary communication is determined by the setting
There are two types of broadcast.
Fig. 2-1 shows the IEBus transmission signal format.
Communication data is transmitted as a sequence of signals called a communication frame. The transmission
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.
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.)
: Unit number (number identifying a device in a group)
Data Sheet S13990EJ3V0DS
PD72042B
11