Configuration and Installation
Chapter 2
SCXI-1162 User Manual
2-24
© National Instruments Corporation
To read from the Module ID Register or the Data Register, follow these steps:
1. Initial conditions:
SS* asserted low.
SERDATIN = don't care.
DAQD*/A = 0.
SLOT0SEL* = 1.
SERCLK = 1 (and has not changed since DAQD*/A went low).
2. For each bit to be read:
Set SERCLK = 0.
SERCLK = 1. This rising edge clocks the data.
Read the level of the SERDATOUT line.
3. Pull DAQD*/A high. This disables further reads from the Register. If you wish, you can
write address FFFF (hexadecimal) to the Address Handler. This selects the Parking Register
and makes the module registers more immune to noise.
4. Pull SLOT0SEL* low to deassert the SS* line and establish conditions for writing a new
slot-select number to the Slot 0 Slot-Select Register.
5. If you are not selecting another slot, write zero to the Slot 0 Slot-Select Register.
Figure 2-10 illustrates a read of the SCXI-1162 Module ID Register.
SS*
SERCLK
0
0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0
SERDATOUT
T
byte 0 = 16
byte 3 = 0
byte 2 = 0
byte 1 = 0
delay
0
0
1
0
SLOT0SEL*
DAQD*/A
Tdelay DAQ D*/A high to SERDATOUT high 600 nsec max
Figure 2-10. SCXI-1162 Module ID Register Timing Diagram
