User Manual

USB-1208LS User's Guide Specifications
20
Digital input/output
Table 7. DIO specifications
Parameter Specification
Digital type
82C55
Number of I/O
16 (Port A0 through A7, Port B0 through B7
Configuration
2 banks of 8
Pull up/pull-down configuration
All pins pulled up to Vs through 47 kΩ resistors (default). Positions
available for pull down to ground. Hardware-selectable through 0 Ω
resistors as a factory option.
Input high voltage
2.0 V min, 5.5 V absolute max
Input low voltage
0.8 V max, –0.5 V absolute min
Output high voltage (IOH = –2.5 mA)
3.0 V min
Output low voltage (IOL = 2.5 mA)
0.4 V max
External trigger
Table 8. Trigger input specifications
Parameter Conditions Specification
Trigger source (Note 4)
External digital
TRIG_IN
Trigger mode
Software-selectable
Level sensitive: user configurable for
TTL level high or low input.
Trigger latency
Burst
25 µs min, 50 µs max
Trigger pulse width
Burst
40 µs min
Input high voltage
3.0 V min, 15.0 V absolute max
Input low voltage
0.8 V max
Input leakage current
±1.0 µA
Note 4: TRIG_IN is protected with a 1.5 kΩ series resistor.
Counter
Table 9. Counter specifications
Parameter Specification
Counter type
Event counter
Number of channels
1
Input source
CTR screw terminal
Input type
TTL, rising-edge triggered
Resolution
32 bits
Schmidt trigger hysteresis
20 mV to 100 mV
Input leakage current
±1 µA
Maximum input frequency
1 MHz
High pulse width
500 ns min
Low pulse width
500 ns min
Input low voltage
0 V min, 1.0 V max
Input high voltage 4.0 V min, 15.0 V max