Chapter 7 Digital I/ODAQ-STC Technical Reference Manual7-6 ©National Instruments Corporation7.5 Pin InterfaceThe I/O signals relevant to the DIO module are listed in the following table.Pin Type Notation:ID TTL input, pull down (50 kΩ.)O4TU Output, 4 mA sink, 2.5 mA source tri-state, pull up (50 kΩ)B18TU Bidirectional, 24 mA sink, 13 mA source tri-state, pull up (50 kΩ)O9TU Output, 9 mA sink, 5 mA source tri-state, pull up (50 kΩ)Table 7-1. Pin InterfacePin Name Type DescriptionCTRL<0..7> O4TU Control<0..7>—These pins serve as general-purpose writestrobes. These could be used to simplify adding board-levelcontrol registers or as clear strobes for the various FIFOs.Related bitfields: Control.DIO0/SDOUT B18TU Digital I/O0/Serial Data Output—This bidirectional pin isone of the eight individually programmable DIO lines. Thispin is also the serial port data output pin. The serial portimplements communication with the SCXI at one of twoselectable clock rates. See also EXTSTROBE/SDCLK.Related bitfields: DIO_Pins_Dir, DIO_Parallel_Data_In_St,DIO_Parallel_Data_Out, DIO_Serial_Data_Out.DIO<1..3> B18TU Digital I/O Lines<1..3>—Individually programmable DIOlines. Related bitfields: DIO_Pins_Dir,DIO_Parallel_Data_In_St, DIO_Parallel_Data_Out.DIO4/SDIN B18TU Digital I/O4/Serial Data Input—This bidirectional pin is oneof the eight individually programmable DIO lines. This pinis also the serial port data input pin. The serial portimplements communication with the SCXI at one of twoselectable clock rates. See also EXTSTROBE/SDCLK.Related bitfields: DIO_Pins_Dir, DIO_Parallel_Date_In_St,DIO_Parallel_Data_Out, DIO_Serial_Data_In_St.DIO<5..7> B18TU Digital I/O Lines<5..7>—Individually programmable DIOlines. Related bitfields: DIO_Pins_Dir,DIO_Parallel_Data_In_St, DIO_Parallel_Data_Out.
