National Instruments SCXI-1163 - page 38

Chapter 2 Configuration and Installation
© National Instruments Corporation 2-23 SCXI-1163 User Manual
To read from the Module ID Register, follow these steps:
1. Initial conditions:
SS* asserted low.
SERDATIN = don't care.
DAQD*/A = 0.
= 1.
SERCLK = 1 (and has not changed since DAQD*/A went low).
2. For each bit to be read:
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 Module ID Register. If you want,
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 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 2-9 illustrates a read of the SCXI-1163 Module ID Register.
SS*
SERCLK
00 00000000000000000000000001
SERDATOUT
T
delay
byte 0 = 18 byte 3 = 0byte 2 = 0byte 1 = 0
0010
SLOT0SEL*
DAQD*/A
T
delay
DAQD*/A high to SERDATOUT high 600 nsec
Figure 2-9. SCXI-1163 Module ID Register Timing Diagram