Slot-select register – National Instruments SCXI-1120 User Manual
Page 69
Register Descriptions
Chapter 4
SCXI-1120 User Manual
4-6
© National Instruments Corporation
Slot-Select Register
The Slot-Select Register contains 16 bits that determine which module in which chassis will be
enabled for communication when the SLOT0SEL* line is high. An SCXI-1000 chassis will
select the appropriate module in its chassis, regardless of the chassis number written. The
Slot-Select Register will shift in the data present on the MOSI line, bit 16 first, when
SLOT0SEL* is low.
Type:
Write-only
Word Size:
16-bit
Bit Map:
15
14
13
12
11
10
9
8
X
X
X
X
X
X
X
CHS4
7
6
5
4
3
2
1
0
CHS3
CHS2
CHS1
CHS0
SL3
SL2
SL1
SL0
Bit
Name
Description
15-9
X
Don't care bits – Unused.
8-4
CHS<4..0>
Chassis Bit 4 through 0 – These bits determine
which chassis is selected. On the SCXI-1000
chassis, these are don't care bits.
3-0
SL<3..0>
Slot Bit 3 through 0 – These bits determine which
slot in the selected chassis is selected.