External Clock Input/Output; Counter - Measurement Computing USB-1608GX User Manual

USB-1608GX User's Guide

External clock input/output

Parameter
Terminal names
Terminal types
Terminal descriptions
Input clock rate
Clock pulse width
Input type
Schmitt trigger hysteresis
Input high voltage
Input low voltage
Output high voltage
Output low voltage
Output current

Counter

Parameter
Terminal names
Number of channels
Resolution
Counter type
Input type
Input source
Counter read/writes rates
(software paced)
Input high voltage
Input low voltage
Schmitt trigger hysteresis
Input frequency
High pulse width
Low pulse width
Table 8. External clock I/O specifications
Specification
AICKI, AICKO
AICKI: Input, active on rising edge
AICKO: Output, power on default is 0 V, active on rising edge
AICKI: Receives sampling clock from external source
AICKO: Outputs the internal A/D sampling clock, or the pulse generated from AICKI
when in external clock mode.
500 kHz max
AICKI: 400 ns min
AICKO: 400 ns min
Schmitt trigger, 33 Ω series resistor, 47 kΩ pull-down to ground
0.4 V to 1.2 V
2.2 V min
5.5 V absolute max
1.5 V max
–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –2.5 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 2.5 mA)
±2.5 mA max
Table 9. Counter specifications
Specification
CTR0, CTR1
2 channels
32-bit
Event counter
Schmitt trigger, 33 Ω series resistor, 47 kΩ pull-down to ground
CTR0 (pin 52)
CTR1 (pin 51)
33 to 8000 reads/writes per second typ, system dependent
2.2 V min, 5.5 V max
1.5 V max, –0.5 V min
0.4 V min, 1.2 V max
20 MHz, max
25 ns, min
25 ns, min
19
Specifications