ZWorld Exp-A/D12, Руководство пользователя

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XP8500
and
Exp-A/D12 PLCBus s 77
The PLCBus consists of the following lines.
• /STBX—negative-going strobe.
• A1X–A3X—three control lines for selecting bus operation.
• D0X–D3X—four bidirectional data lines used for 4-bit operations.
• D4X–D7X—four additional data lines for 8-bit operations.
• /AT—attention line (open drain) that may be pulled low by any device,
causing an interrupt.
The PLCBus may be used as a 4-bit bus (D0X–D3X) or as an 8-bit bus
(D0X–D7X). Whether it is used as a 4-bit bus or an 8-bit bus depends on
the encoding of the address placed on the bus. Some PLCBus expansion
cards require 4-bit addressing and others (such as the XP8700) require
8-bit addressing. These devices may be mixed on a single bus.
Two independent buses, the LCD bus and the PLCBus, exist on the single
connector.
The LCD bus consists of the following lines.
• LCDX—positive-going strobe.
• /RDX—negative-going strobe for read.
• /WRX—negative-going strobe for write.
• A0X—address line for LCD register selection.
• D0X-D7X—bidirectional data lines (shared with expansion bus).
The LCD bus is used to connect Z-World’s OP6000 series interfaces or to
drive certain small liquid crystal displays directly. Figure A-2 illustrates
the connection of an OP6000 interface to a PLCBus header.
Yellow wire
on top
PLCBus Header
Note position of connector
relative to pin 1.
From OP6000
KLB Interface Card
Header J2
Pin 1
Figure A-2. OP6000 Connection to PLCBus Header