Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi User Manual

Page 306

III. COMMAND REFERENCES - 15. Command References

15A. Driver488/DRV Commands

Personal488 User’s Manual, Rev. 3.0

III-291

EXAMPLES

PRINT#1,"ENTER#100 BUFFER

&H2000:0"

Read 100 characters into memory at &H20000.

PRINT#1,"ENTER#100 BUFFER

&H20100 EOI"

Read 100 characters, or until EOI is detected into

memory at absolute location 20100.

PRINT#1,"BUFFERED"
INPUT#2,NBUFFERED

PRINT#1,"ENTER# 100 BUFFER

262144 CONTINUE"

Read 100 characters as before, but allow the

program to continue while the transfer is taking
place.

PRINT#1,"WAIT"

Wait until the transfer has completed.

PRINT#1,"ENTER#100 BUFFER

262144CONTINUE EOI"

Read 100 characters as before, but stop if the EOI

(end or identify) signal is encountered.

PRINT#1,"WAIT"

Wait until the transfer has completed.

PRINT#1,"BUFFERED"
INPUT#2,NBUFFERED

Get the number of characters actually read.

In Peripheral mode, the

ENTER #count BUFFER

command receives data from the bus under control

of the Active Controller. The Active Controller must put Driver488 into the

Listen

state and

configure some other device to provide it with data. The

Listen

state can be checked with the

STATUS

command, or can cause an interrupt via the

ARM

command. A time-out error occurs (if

enabled) if Driver488 does not receive a data byte within the time out period after issuing the

ENTER #count BUFFER command

. The character count

count

must be specified, and is the

maximum number of characters that is transferred.

ENTER #count BUFFER

does not detect the input terminator unless it is explicitly specified in the

command. Otherwise the specified number of characters is received. The number of characters
actually received can be checked with the

BUFFERED

command.

CONTINUE

is specified, then Driver488 returns control to the user’s program as soon as possible,

without waiting for the transfer to be completed. It does, however, wait for the first byte to check for
time-out unless a time-out value of

had been specified by a

TIMEOUT

command. Because of

hardware limitations, the

CONTINUE

may not return until a substantial portion of the transfer is

complete if Driver488 is configured for no interrupts.

CONTINUE

transfers are not finished until Driver488 has had an opportunity to “clean up” and complete

the transfer. This “clean up” is usually automatic: Driver488 implicitly performs a

WAIT

command

before performing any bus command. The program can itself use the

WAIT

command to guarantee that

the transfer is complete.

All characters read, including the bus terminator, if any, are placed in the memory buffer. No
terminator translation is performed. The

EOL IN

terminator is not put into the memory buffer.

EOL

SYNTAX

EOL [name][IN|OUT] {term [term]|NONE}

name

is the name of an External Device. If name is not specified, then EOL acts

on the I/O adapter.

OUT

specifies whether the input or output terminators are being set. If

neither

nor

OUT

is specified, then both terminators are set identically.

term

is one of

$char

, or

‘X

, specifying a terminator character.

NONE

may be specified instead of term to indicate that no

EOL

terminators are

used.

RESPONSE

None

MODE

Any

BUS STATES

None

SEE ALSO

TERM, ENTER, OUTPUT

EXAMPLES

See next page.