Power Connections; Timing Connections; Data Acquisition Timing Connections - National Instruments AT-MIO-16 User Manual

Signal Connections
The RTSI switch is a National Instruments custom integrated circuit that acts as a 7x7 crossbar
switch. Pins B<6..0> are connected to the seven RTSI bus trigger lines. Pins A<6..0> are
connected to seven signals on the board. The RTSI switch can drive any of the signals at pins
A<6..0> onto any one or more of the seven RTSI bus trigger lines and can drive any of the seven
trigger line signals onto any one or more of the pins A<6..0>. This signal trigger produces a
completely flexible signal interconnection scheme for any AT Series board sharing the RTSI bus.
You program the RTSI switch via its select and data inputs.
On the AT-MIO-16 board, nine signals are connected to pins A<6..0> of the RTSI switch with
the aid of additional drivers. The signals GATE1, OUT1, OUT2, OUT5, FOUT, and
STOPTRIG are shared with the AT-MIO-16 I/O connector and Am9513A counter/timer. The
signal SOURCE5 is connected to the Am9513A SOURCE5 pin. The I/O connector and the data
acquisition timing circuitry share the EXTCONV* and STARTTRIG* signals. Through these
onboard interconnections, you can control the AT-MIO-16 general-purpose and data acquisition
timing over the RTSI bus as well as externally, and use the AT-MIO-16 and the I/O connector to
supply timing signals to other AT boards connected to the RTSI bus.

Power Connections

Pins 34 and 35 of the I/O connector supply +5 V from the PC AT power supply. These pins are
referenced to DIGGND and you can use them to power the external digital circuitry.
• Power rating:
Warning: These +5 V power pins should
ground or to any other voltage source on the AT-MIO-16 or any other device.
Doing so can damage the AT-MIO-16 and the PC AT. National Instruments is
liable for damages resulting from such a connection.
NOT

Timing Connections

Pins 36 through 50 of the I/O connector are connections for timing I/O signals. Pins 36 through
40 carry signals used for data acquisition timing. These signals are explained in the next section,
Data Acquisition Timing Connections. Pins 41 through 50 carry general-purpose timing signals
produced by the onboard Am9513A counter/timer. These signals are explained in the General-
Purpose Timing Signal Connections section later in this chapter.

Data Acquisition Timing Connections

The data acquisition timing signals are SCANCLK, EXTSTROBE*, STARTTRIG*,
STOPTRIG, and EXTCONV*.
SCANCLK is an output signal that generates a high-to-low edge whenever an A/D conversion
begins. SCANCLK pulses only when scanning is enabled on the AT-MIO-16. SCANCLK is
normally high and pulses low for approximately 1 µs after the A/D conversion begins. The low-
to-high edge signals that the input signal has been acquired. You can use this signal to clock
external analog input multiplexers. One LS TTL gate drives the SCANCLK signal.
AT-MIO-16 User Manual
0.5 A at +5 V ± 10%
be directly connected to analog or digital
NOT
3-16 © National Instruments Corporation
Chapter 3