488 CONTROLLER
86
For data transfer on the IEEE 488, the Active Controller must
a)
Unlisten all devices to protect against eavesdroppers.
b)
Designate who will talk by addressing a device to talk.
c)
Designate all the devices who are to listen by addressing those devices to listen.
d)
Indicate to all devices that the data transfer can take place.
Figure 8-1. IEEE 488 bus structure.
Device 1
System Controller
Able to Talk,
Listen, and Control
Device 2
DMM
Able to Talk
and Listen
Device 3
Printer
Only Able to Listen
Device 4
Frequency Counter
Only Able to Talk
To Other Devices
Data Bus
Data Byte
Transfer
Control
General
Interface
Management
DAV
NRFD
NDAC
IFC
ATN
SRQ
REN
EOI
DIO1-8
