Theory of Operation
Chapter 3
SCXI-1160 User Manual
3-6
© National Instruments Corporation
The digital interface circuitry is divided into a data acquisition section and an SCXIbus section.
The SCXI-1160 connects to the SCXIbus via a 4x24 metral receptacle and to the data acquisition
board via a 50-pin ribbon-cable header. The digital interface circuitry buffers the digital signals
from the data acquisition board and the SCXIbus and sends signals back and forth between the
data acquisition board and the SCXIbus.
Digital Control Circuitry
Figure 3-4 diagrams the SCXI-1160 digital control.
MOD ID Register
Data Register
Serial Data Out
Address
Handler
NC <15..0>
NO <15..0>
Buffered
Serial Data In
Buffered Digital
Control Signals
Status Register
Figure 3-4. SCXI-1160 Digital Control
The digital control section consists of the Address Handler, the Data Register, the Module ID
Register, and the Status Register.
The Address Handler is the register to which you first write an address to specify with which
write or read register you want to communicate. The Address Handler is a two-byte, serial-in,
parallel-out register with address decoding. Refer to the Timing Requirements and
Communication section in Chapter 2, Configuration and Installation, and to Chapter 4, Register
Descriptions, for further details.
The Data Register is a four-byte, serial-in, parallel-out shift register with relay drive capabilities.
Data is received on the MOSI line from either Slot 0 or the data acquisition board when SS* is
enabled, D*/A indicates data transfer (D*/A low), and the Data Register address is selected in the