Control Functions
PSI BOX PLUS+ Reference
SPD.
Sends Serial Poll Disable Command.
_____
________________________________
Purpose.
Disables serial poll mode.
__________
The PSI BOX asserts ATN, if not already true, and
becomes the active controller, then the IEEE command SPD, hex
019h decimal 25, is sent over the IEEE bus. After the command
has been sent the ATN remains true, PSI BOX is the active
controller.
The SPD command is used automatically in the SPOLL
routine but it can be called separately to finish your own serial
poll routine. The SPD command can also be sent by using CMD
25 or CMD 153
Format.
SPD
_________
Params.
None.
_________
Returns.
Only if used as part of a full serial poll sequence
__________
would a response from the IEEE bus be forthcoming.
Example.
BUS SPD
:REM ISSUE COMMAND
___________
Bus Activity.
___________
_
assert ATN if not already so
SPD
Example.
A COMPLETE SERIAL POLL ROUTINE.
___________
BUS SPE TALK 4 READ SPD UNT
BUS STATUS
:REM READ STRING
SP at position 11
:REM HOLDS REPLY.
Bus Activity.
___________
_
assert ATN if not already so
SPE
TAD 4
drop ATN and read serial poll status byte.
SPD
UNT
Chapter 8
Page 143
Содержание P.S.I. BOX
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