Measurement-computing Digital488 Uživatelský manuál stáhnout pdf (Strana 46)

Section 3 Command Descriptions

3.16

F4 Format - Binary

In the

binary format, no error checking is performed and caution

must

exercised when using this mode to avoid locking the IEEE bus.

When addressed to listen, the

Digital488

expects the "D"

prefix followed by five

bytes of data beginning with PORT5 without the "Z" suffix. If any digital I/O port is

configured as an input, the data to that input port will be ignored.

When the

Digital488

is addressed to talk (

) it asserts

Inhibit

, reads the data

from all ports, unasserts

Inhibit

and outputs 5 bytes beginning with PORT5 with EOI

asserted on the last bye. Bus terminators, with the exception of EOI, are

not

appended to

the output. After output the

Digital488

must be re-addressed to talk to perform

subsequent reads.

EDR

(

) may also be used to capture data in this format.

F5 Format - High Speed Binary

In the

high speed binary format, the command interpreter is disabled. When

addressed to listen, the

Digital488

treats all bytes received as data to be output to the

Digital I/O ports. Each time it receives five bytes

detects EOI asserted, it pulses the

Data Strobe

for approximately 15 microseconds. Data is expected in a PORT5, PORT4,

PORT3, PORT2, PORT1 sequence. If only two bytes are received, with EOI asserted on

the second byte, the

Digital488

will update PORT5 with the first byte received, PORT4

with the second and pulse the

Data Strobe

. Since the interface treats all received

characters as data, the

command will not be recognized.

To place the

Digital488

in the

format, the 3 character string "

F5X

" should be

the last command sent to the interface

without

terminators. Any characters appended to

this command, such as carriage return or line feed, will be considered data and the output

ports will reflect those character values.

When addressed to talk in this format it asserts

Inhibit

, reads the data from all

ports, unasserts

Inhibit

and outputs the binary data to the bus with EOI asserted on the

fifth byte. When the last data byte is transferred, the data is read again in anticipation of

another data transfer. If

Inhibit

is used to sequence external hardware, this line will pulse

N+1 times; where N is the number of total (5 byte) data transfers. In this format the

Digital488

does

not

have to be re-addressed to talk to read the ports multiple times.

EDR

cannot be used to capture data in the

high speed binary format.

1 2 ... 41 42 43 44 45 46 47 48 49 50 51 ... 82 83

Komentáře k této Příručce

Žádné komentáře

Measurement-computing Digital488 Uživatelský manuál Strana 46

Komentáře k této Příručce

Související produkty a manuály pro Hardware Measurement-computing Digital488