Power-On State; Changing Dio Power-On State To Pulled Low - National Instruments DAQPad-6020E User Manual

82C55A configurations as modes, whereas NI-DAQ, LabWindows/CVI, and LabVIEW
documentation refers to them as handshaking and no handshaking.
Configuration Terminology
NI 6016 or Instruments
NI 6025E
Mode 0 No
(Basic I/O) Handshaking
Mode 1 Handshaking
(Strobed Input)
Mode 1 Handshaking
(Strobed Output)
Mode 2 Handshaking
(Bidirectional Bus)
*
Indicates that the signal is active low.
1
Denotes port 1 handshaking signals.
2
Denotes port 2 handshaking signals.

Power-On State

© National Instruments Corporation
Table 4-1. Configuration Terminology and Signal Assignments
National
Software P3.7
I/O
I/O
*1
OBF
*1
OBF
(NI 6016 and NI 6025E Devices Only)
resistors that control the state of the DIO lines, P1.<0..7>, P2.<0..7>,
P3.<0..7>. At power-on, each DIO line is configured as an input and pulled
high.
You can change the power-on state of individual lines from pulled high to
pulled low by adding your own external resistors.

Changing DIO Power-On State to Pulled Low

Each DIO line is pulled to V
resistor. To pull a specific line low, add a pull-down resistor (R
the line and ground so the maximum value on the line is 0.4 VDC. The DIO
lines provide a maximum of 2.5 mA at 3.7 V in the high state. Using the
largest possible resistor ensures that you do not use more current than
necessary to perform the pull-down task.
Ensure the value of the resistor is not so large that leakage current from the
DIO line, along with the current from the 100 kΩ pull-up resistor, drives the
Signal Assignments
P3.6 P3.5 P3.4
I/O I/O I/O
1 *1
I/O IBF STB
*1
ACK I/O I/O
*1 1 *1
ACK IBF STB
The NI 6016 and NI 6025E contain bias
(approximately +5 VDC) with a 100 kΩ
cc
4-3
Chapter 4
P3.3 P3.2 P3.1
I/O I/O I/O
1 *2
INTR STB IBFB
1 *2 *2
INTR ACK OBF
1
INTR I/O I/O
E Series User Manual
Digital I/O
P3.0
I/O
2 2
INTR
2
INTR
I/O
) between
L