Chapter 7
Digital I/O
DAQ-STC Technical Reference Manual
7-14
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National Instruments Corporation
DIO_HW_Serial_Timebase
bit: 10
type: Write
in: DIO_Control_Register
address: 11
This bit selects the timebase used for the EXTSTROBE/SDCLK signal during
hardware-controlled serial digital I/O:
0: SERIAL_TIMEBASE divided by 12 (1.2
µ
s clock).
1: IN_TIMEBASE2.
You need to set DIO_Serial_Out_Divide_By_2 to 0 if a 10 MHz oscillator is used and to 1 if
a 20 MHz oscillator is used to obtain the frequency indicated in parentheses. Use
DIO_HW_Serial_Enable to enable hardware-controlled serial digital I/O. Related bitfields:
DIO_Serial_Out_Divide_By_2, DIO_HW_Serial_Enable.
DIO_Parallel_Data_In_St
bits: <0..7>
type: Read
in: DIO_Parallel_Input_Register
address: 7
This bitfield is used for digital input on DIO<0..7>. If a DIO line is configured for output, the
corresponding bit in this register will reflect the output state.
DIO_Parallel_Data_Out
bits: <0..7>
type: Write
in: DIO_Output_Register
address: 10
This bitfield is used for data to be output in parallel on DIO<0..7>.
DIO_Pins_Dir
bits: <0..7>
type: Write
in: DIO_Control_Register
address: 11
This bitfield selects the directions of the bidirectional pins DIO<0..7>:
0: Input.
1: Output.
Use this field to configure all eight lines on a per line basis.
DIO_Serial_Data_In_St
bits: <0..7>
type: Read
in: DIO_Serial_Input_Register
address: 28
This bitfield is used for serial digital input on DIO4. Do not attempt to read from this register
while serial digital I/O is in progress. Related bitfields: DIO_Serial_IO_In_Progress.
DIO_Serial_Data_Out
bits: <8..15>
type: Write
in: DIO_Output_Register
address: 10
This bitfield is used for data to be serially output on DIO0.