Read – Measurement Computing Analyzer488 User Manual

Page 152

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Section 4

Serial Controller

4.58

READ

The READ command is used to accept data from the bus when in the Low Level

Controller Mode and return a machine readable bus status string.

READ

may only be used when the Analyzer488 is in the Listen State (see

LISTEN

) and handshaking is set to STEP (see HANDSHAKE). READ performs an

acceptor handshake. The STEP command is not required when using the READ
command since the handshake is automatically performed when READ is executed.

This command does not have a query option.

TYPE

Low Level Controller command

SYNTAX

READ

RESPONSE

Response is dependent on the data currently on the bus. Two
hexadecimal bytes are returned in the following format:

Hex Byte 1

Hex Byte 2

(bit positions)

(bit positions)

(Control and Handshake Lines)

(Data Lines)

8 7 6 5

4 3

2 1

8 7 6 5 4 3 2 1

REN IFC SRQ EOI DAV NRFD NDAC ATN D8

D1

MODE

Low level controller

BUS STATES

None

QUERY

None

RESPONSE

EXAMPLES

PRINT#1,"CONTROLLER OFF"
PRINT#1,"ASSERT IFC ATN REN"
PRINT#1,"UNASSERT IFC"
PRINT#1,"TALK"
PRINT#1,"HANDSHAKE STEP"

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