Chapter 3
Signal Connections
© National Instruments Corporation
3-19
AT-MIO-16 User Manual
General-Purpose Timing Signal Connections
The general-purpose timing signals include the GATE, SOURCE, and OUT signals for the
Am9513A counters 1, 2, and 5, and the FOUT signal that the Am9513A generates. You can use
the Am9513A counter/timer counters 1, 2, and 5 for general-purpose applications such as pulse
and square wave generation, event counting, and pulse-width, time-lapse, and frequency
measurements. For these applications, you can directly apply SOURCE and GATE signals to the
counters from the I/O connector and program the counters for various operations. Figure 3-14
shows a block diagram of the timing I/O circuitry.
GATE4
RTSI Bus
/
2
/
16
1 MHz CLK
DATA<15..0>
Am9513 RD/WR
CONVERT
SCANCLK
MUXCTRCLK
Data
Acquisition
Timing
SOURCE4
SOURCE3
OUT1
OUT3
OUT4
OUT5
GATE3
Am9513A
5
Channel
Counter/
Timer
÷
10
GATE5
SOURCE5
OUT5
GATE2
SOURCE2
OUT2
GATE1
SOURCE1
OUT1
FOUT
I/O Connector
STOPTRIG
Flip
Flop
GATE4
PC
A
T
I/O Channel
(10 MHz)
MYCLK
Figure 3-14. Timing I/O Circuitry Block Diagram
The Am9513A contains five independent 16-bit counter/timers, a 4-bit frequency output channel,
and five internally generated timebases. You can program the five counter/timers to operate in
several useful timing modes.
The Am9513A clock input is one-tenth the MYCLK frequency selected by the W5 jumpers. The
factory-default setting for MYCLK is 10 MHz, which generates a 1-MHz clock input to the
Am9513A. The Am9513A uses this clock input to generate five internal timebases. The
counter/timers and the frequency output channel can use these timebases as clocks. When
MYCLK is 10 MHz, the five internal timebases normally used for AT-MIO-16 timing functions
are 1 MHz, 100 kHz, 10 kHz, 1 kHz, and 100 Hz.
