Chapter 2
Configuration and Installation
© National Instruments Corporation
2-27
SCXI-1120 User Manual
The digital output signal is pin 26:
•
Pin 26 is SERDATOUT and is equivalent to SCXIbus MISO when jumper W43 is in
position 1.
The digital I/O signals of the SCXI-1120 match the digital I/O lines of the MIO-16 board. When
used with an SCXI-1341, SCXI-1342, or SCXI-1344 cable assembly, the SCXI-1120 signals
match the digital lines of the Lab-NB/Lab-PC+/Lab-LC boards and the PC-LPM-16 board,
respectively. Table 2-9 lists the equivalences. For more information, consult Appendix E,
SCXI-1120 Cabling.
Table 2-9. SCXIbus to SCXI-1120 Rear Signal Connector to
Data Acquisition Board Pin Equivalences
SCXIbus Line
SCXI-1120
Rear Signal
Connector
MIO-16 Board
Lab-NB/Lab-PC/
Lab-PC+/Lab-LC
PC-LPM-16
MOSI
SERDATIN
ADIO0
PB4
DOUT4
D*/A
DAQD*/A
ADIO1
PB5
DOUT5
INTR*
SLOT0SEL*
ADIO2
PB6
DOUT6
SPICLK
SERCLK
EXTSTROBE*
PB7
DOUT7
MISO
SERDATOUT
BDIO0
PC1
DIN6
The digital timing signals are pins 36 and 43:
•
Pin 36 is used as a clock by the SCXI-1120 to increment the MUXCOUNTER after each
conversion by the data acquisition board during scanning. This signal is referred to as
SCANCLK. See Chapter 3, Theory of Operation, for a description of MUXCOUNTER.
•
Pin 43 is a reserved digital input.
The following specifications and ratings apply to the digital I/O lines.
Absolute maximum voltage
input rating
5.5 V with respect to DIG GND
Digital input specifications (referenced to DIG GND):
V
IH
input logic high voltage
2 V minimum
V
IL
input logic low voltage
0.8 V maximum
I
I
input current leakage
±
1
µ
A maximum
Digital output specifications (referenced to DIG GND):
V
OH
output logic high voltage
3.7 V minimum at 4 mA maximum
V
OL
output logic low voltage
0.4 V maximum at 4 mA maximum
