Control Functions
PSI BOX PLUS+ Reference
PPU.
Sends Parallel Poll Unconfigure.
_____
____________________________
Purpose.
The universal command Parallel Poll Unconfigure is
__________
sent to the IEEE bus. Resets ALL devices with the Parallel Poll
ability to the idle state.
The PSI BOX asserts ATN and becomes the active
controller, then the IEEE command PPU, hex 15h decimal 21, is
sent over the IEEE bus. After the command has been sent the
ATN remains true, PSI BOX is the active controller.
The PPU command is used to make all devices that have
the Parallel poll ability unable to respond to a parallel poll
command.
For a device to respond to the Parallel Poll it must receive
a PPC and PPE command sequence or be programmed using the
CONFIGURE command. All devices power up in the PPU state.
i.e they cannot respond to Parallel Poll.
The PPC command can also be sent by using CMD 21 or
CMD 149.
Format.
PPC
_________
Params.
None.
_________
Returns.
None.
__________
Example.
________
_
BUS PPU
Bus Activity.
___________
_
assert ATN if not already so
PPU
Chapter 8
Page 135
Содержание P.S.I. BOX
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