National Instruments SCXI-1120 User Manual

Also see for SCXI-1120: Quick start guide User manual CALIBRATION PROCEDURE Instructions for safe use User guide

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Chapter 2 Configuration and Installation© National Instruments Corporation 2-31 SCXI-1120 User ManualSLOT0SEL*SERDATINSERCLKSS*01 0 0 0 0 1 1 0 0 0 0 1 1 1 1Figure 2-15. Configuration Register Write Timing DiagramTo read from the Module ID Register, follow these steps:1. Initial conditions:SS* asserted low.SERDATIN = don't care.DAQD*/A = 1. Make sure DAQD*/A does not go low or erroneous data will be writtento the Configuration Register.SLOT0SEL* = 1.SERCLK = 1 (and has not changed since SS* went low).2. For each bit to be read:SERCLK = 0.SERCLK = 1. Clock the data.Read the level of the SERDATOUT line.3. Pull SLOT0SEL* low to deassert the SS* line and establish conditions for writing a newslot-select number to the Slot 0 Slot-Select Register.4. If you are not selecting another slot, you should write zero to the Slot 0 Slot-Select Register.Figure 2-16 illustrates a read of the SCXI-1120 Module ID Register.SLOT0SEL*SS*SERCLK0 10 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 00SERDATOUT Tdelaybyte 0 = 4 byte 3 = 0byte 2 = 0byte 1 = 0Tdelay SS* high to SERDATOUT high 350 nsec maximumFigure 2-16. SCXI-1120 Module ID Register Timing DiagramFor further details on programming these signals, refer to Chapter 5, Programming.