Chapter 3
Theory of Operation
© National Instruments Corporation
3-3
SCXI-1163 User Manual
SCXIbus Connector Signal Descriptions
Pin
Signal Name
Description
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 0 Slot-Select Register. Open
collector. Output.
A21, B21, C21,
CHSGND
Chassis Ground – Digital and analog ground reference.
D21
A22, B22, C22,
V+
Positive Supply – +18.5 to +25 V.
D22
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.
B24
SS*
Slot Select – When low, enables module
communication over the SCXIbus. Totem pole. Input.
* Indicates active low.
All other pins are not connected.
MOSI, MISO, SPICLK, and SS* form a synchronous communication link that conforms with
SPI using an idle-high clock and second-edge data latching. D*/A, INTR*, and RESET* are
additional control signals.
When the module is in an SCXI-1000 or SCXI-1001 chassis, the data acquisition board must tap
into the open-collector backplane signal lines via the module rear signal connector as a master to
write to the module. You must set the jumpers to serial mode and configure them for a DIO
board or an MIO board as needed to create this interface. Table 3-1 shows the signal connections
from the rear signal connector to the backplane.
