Measurement-computing Digital488 Uživatelský manuál stáhnout pdf (Strana 65)

Section 4 IEEE 488 Primer

4.5

4.4.2 Interface Clear (IFC)

The

IFC

line is used only by the

System Controller

. It is used to place all

bus devices in a known state. Although device configurations vary, the

IFC

command usually places the devices in the Talk and Listen Idle states (neither

Active

Talker

nor

Active Listener

4.4.3 Remote Enable (REN)

When the

System

Controller

sends the

REN

command, bus devices will

respond to remote operation. Generally, the

REN

command should be issued before

any bus programming is attempted. Only the

System

Controller

has control of the

Remote

Enable

line.

4.4.4 End or Identify (EOI)

The

EOI

line is used to signal the last byte of a multibyte data transfer. The

device that is sending the data asserts

EOI

during the transfer of the last data byte.

The

EOI

signal is not always necessary as the end of the data may be indicated by

some special character such as carriage return.

The

Active

Controller

also uses

EOI

to perform a

Parallel

Poll

simultaneously asserting

EOI

and

ATN

4.4.5 Service Request (SRQ)

When a device desires the immediate attention of the

Active

Controller

asserts

SRQ

. It is then the Controller's responsibility to determine which device

requested service. This is accomplished with a

Serial Poll

or a

Parallel Poll

1 2 ... 60 61 62 63 64 65 66 67 68 69 70 ... 82 83

Komentáře k této Příručce

Žádné komentáře

Measurement-computing Digital488 Uživatelský manuál Strana 65

Komentáře k této Příručce

Související produkty a manuály pro Hardware Measurement-computing Digital488