Chapter 3
Signal Connections
© National Instruments Corporation
3-23
AT-MIO-16 User Manual
Signal
Source
33
DIGGND
Counter
OUT
SOURCE
GATE
+5 V
4.7 k
Ω
I/O Connector
AT-MIO-16 Board
Gate
Source
Figure 3-17. Frequency Measurement Application
You can concatenate two or more counters by tying the OUT signal from one counter to the
SOURCE signal of another counter. You can then treat the counters as one 32-bit or 48-bit
counter for most counting applications.
The GATE, SOURCE, and OUT signals for counters 1, 2, and 5, and the FOUT output signal are
tied directly from the Am9513A input and output pins to the I/O connector. In addition, the
GATE, SOURCE, and OUT1 pins are pulled up to +5 V through a 4.7 k
Ω
resistor.
The following input and output ratings and timing specifications apply to the Am9513A signals:
•
Absolute maximum voltage input rating
-0.5 V to +7.0 V with respect to DIGGND
•
Am9513A digital input specifications (referenced to DIGGND):
–
V
IH
input logic high voltage
2.2 V min
–
V
IL
input logic low voltage
0.8 V max
–
Input load current
±
10
µ
A max