Appendix C SCXIbus Connector
© National Instruments Corporation C-3 SCXI-1121 User Manual
SCXIbus Connector Signal Descriptions Pin Signal
Name Description
A1, B1, C1, D1,
A2, D2,A3, B3,
C3, D3, A4, D4,
A5, B5, C5, D5,
A6, D6
GUARD Guard—Shields and guards the analog bus lines from noise.
B2 AB0+ Analog Bus 0+ —Positive analog bus 0 line. Used to multiplex
several modules to one analog signal.
C2 AB0– Analog Bus 0– —Negative analog bus 0 line. Used to multiplex
several modules to one analog signal.
C13-C17, A21,
B21, C21, D21 CHSGND Chassis Ground—Digital and analog ground reference.
C18 RSVD Reserved.
A19 RESET* Reset—When pulled low, reinitializes the module to its power-up
state. Totem pole. Input.
B19 MISO Master-In Slave-Out—Transmits data from the module to the
SCXIbus. Open collector. I/O.
C19 D*/A Data/Address—Indicates to the module whether address
information or data information is being sent to the module on
MOSI. Open collector. I/O.
D19 INTR* Interrupt—Active low. Causes data that is on MOSI to be written
to the Slot-Select Register in Slot 0. Open collector. Output.
A20, B20, C20,
D20 V– Negative Analog Supply— –18.5 to –25 V.
A22, B22, C22,
D22 V+ Positive Analog Supply— +18.5 to +25 V.
A23, D23 +5 V +5 VDC Source—Digital power supply.
B23 SPICLK Serial Peripheral Interface (SPI) Clock—Clocks the serial data
on the MOSI and MISO lines. Open collector. I/O.
C23 MOSI Master-Out Slave-In—Transmits data from the SCXIbus to the
module. Open collector. I/O.