Keithley 486 Instruction Manual page 102

SECTION4
IEEE-488 Reference
4.2.9 K - EOI and Bus Hold-Off
Purpose To enable/&able EOI and bus hold-off on X.
Format
Kn
Parameters KO Enable EOI; Enable bus hold-off on X
Kl Disable EOI; Enable bus hold-off on X
K2 Enable EOI; Disable bus hold-off on X
K3 Disable EOI; Disable bus hold-off on X
Default Upon power-up, or after the instrument receives a DCL. or SDC command, the instrument will
rehxn to the K option that was saved as the default condition.
Description
The EOI line provides one method to positively identify the last byte in the data string sent by
the instrument. When enabled, EOI will be asserted with the last byte the inskunent sends
over the bus.
Bus hold-off allows the instrument to temporax+ly hold up bus operation via the NRFD line
when it receives the X character until all co mmands are processed. Hold-off will ensure that all
commands havebeen executed at the time the bus is released. The hold-off period depends on
the commands being processed. Table 4-2 lists hold off limes for a number of different com-
mands.
Programming
Notes
1. Some controllers rely on EOI to terminate their input sequences. Suppressing EOI may
cause the controlIer input sequence to hang.
2. When enabled, EOIwill be asserted with the last byte in the terminator (if enabled), or with
the last byte in the data string if the terminator has been disabled.
Programming
Examples
OUTPUT 722;'Klx"
0LmPu-r 7z;'KOY
! Disable EOI; enable hold-off on X
! Enable EOI; enable hold-off on X
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