National Instruments AT-MIO-64F-5, Руководство пользователя

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Configuration and Installation Chapter 2
AT-MIO-64F-5 User Manual 2-10 © National Instruments Corporation
Selecting a bipolar range for a particular DAC means that any data written to that DAC will be
interpreted as two's complement format. In two's complement mode, data values written to the
analog output channel range from -2,048 to +2,047 decimal (800 to 7FF hex). If unipolar range
is selected, data is interpreted in straight binary format. In straight binary mode, data values
written to the analog output channel range from 0 to 4,095 decimal (0 to FFF hex).
Digital I/O Configuration
The AT-MIO-64F-5 contains eight lines of digital I/O for general-purpose use. The eight digital
I/O lines supplied are configured as two 4-bit ports. Each port can be individually configured
through programming of a register in the board register set as either input or output. At system
startup and reset, the digital I/O ports are both configured for input.
Board and RTSI Clock Configuration
When multiple AT Series boards are connected via the RTSI bus, you may want all of the boards
to use the same 10 MHz clock. This arrangement is useful for applications that require
counter/timer synchronization between boards. Each AT Series board with a RTSI bus interface
has an onboard 10 MHz oscillator. Thus, one board can drive the RTSI bus clock signal, and the
other boards can receive this signal or disconnect from it.
Many functions performed by the AT-MIO-64F-5 board require a frequency timebase to
generate the necessary timing signals for controlling ADC conversions, DAC updates, or
general-purpose signals at the I/O connector. You select this timebase through programming one
of the registers in the AT-MIO-64F-5 register set.
The AT-MIO-64F-5 can use either its internal 10 MHz timebase, or it can use a timebase
received over the RTSI bus. In addition, if the board is configured to use the internal timebase, it
can also be programmed to drive its internal timebase over the RTSI bus to another board that is
programmed to receive this timebase signal. This clock source, whether local or from the RTSI
bus, is then divided by 10 and used as the Am9513A frequency source. The default
configuration at startup is to use the internal timebase without driving the RTSI bus timebase
signal.
Hardware Installation
You can install the AT-MIO-64F-5 in any available 16-bit expansion slot in your AT Series
computer. However, to achieve best noise performance, you should leave as much room as
possible between the AT-MIO-64F-5 and other boards and hardware. The AT-MIO-64F-5
does
not work if installed in an 8-bit expansion slot (PC Series). After you have made any necessary
changes, verified, and recorded the switches and jumper settings (a form is included for this
purpose in Appendix F,
Customer Communication ), you are ready to install the AT-MIO-64F-5.