Section Five
Programming the GPIB-LPT
© National Instruments Corporation
5-5
GPIB-LPT User Manual
Control Register (CTRL)
PC Address:
Base I/O A 2 (hex)
Attributes:
Write Only
7
6
5
4
3
2
1
0
X
X
X
IRQEN
SLCTIN
INIT*
AUTOFD
STROBE
W
Printer control signals are stored at this address to be read by the system microprocessor.
Bit
Mnemonic
Description
7 - 5w
X
Don't Care Bits 7 through 5.
Can be written as a 0 or 1.
4w
IRQEN
Interrupt Request Enable Bit
When this bit is set, an interrupt will occur when ACK* changes
from active to inactive.
3w
SLCTIN
Select In Bit
When this bit is set, the GPIB-LPT can source data onto the
GPIB data lines.
2w
INIT*
Initialize Bit
Setting and then clearing this bit initializes the GPIB-LPT.
1w
AUTOFD
Automatic Linefeed Bit
When this bit is set to one, a linefeed is automatically set after
each line is sent to the printer. This bit is not used by the GPIB-
LPT because there is no analogous signal for GPIB printers.
0w
STROBE
Data Strobe Bit
Pulsing this bit from low to high clocks the contents of the
DATA register into the secondary data latch of the GPIB-LPT
and initiates a GPIB Source Handshake. If the printer is offline,
the GPIB-LPT first sends the listen address of the printer.
