Measurement Computing USB-7204 - Manual (Page 24)

USB-7204 User's Guide Specifications
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Digital input/output
Table 11. Digital I/O specifications
Parameter Specification
Digital type CMOS
Number of I/O 16 (Port 0 bit 0 through bit 7, Port 1 bit 0through bit 7)
Configuration 2 banks of 8
Pull up/pull-down configuration All pins configurable via jumpers (JP1 and JP2) to Vs or Ground via 47 k resistors.
JP1 configures Port 1, and JP2 configures Port 0.
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) 3.8 V min
Output low voltage
(IOL = 2.5 mA) 0.7 V max
Power on and reset state Input
External trigger
Table 12. Digital trigger specifications
Parameter Conditions Specification
Trigger source (Note 7) External digital TRIG_IN
Trigger mode Software-selectable
Edge sensitive: user configurable for CMOS compatible
rising or falling edge.
Trigger latency 10 µs max
Trigger pulse width 1 µs min
Input high voltage 4.0 V min, 5.5 V absolute max
Input low voltage 1.0 V max, –0.5 V absolute min
Input leakage current ±1.0 µA
Note 7: TRIG_IN is
a Schmitt trigger input protected with a 1.5 kΩ series resistor.
External clock input/output
Table 13. External clock I/O specifications
Parameter Conditions Specification
Pin name SYNC
Pin type Bidirectional
Software-selectable direction Output (default) Outputs internal A/D pacer clock.
Input Receives A/D pacer clock from external source.
Input clock rate 50 KHz, max
Clock pulse width Input mode 1 µs min
Output mode 5 µs min
Input leakage current Input mode ±1.0 µA
Input high voltage 4.0 V min, 5.5 V absolute max
Input low voltage 1.0 V max, –0.5 V absolute min
Output high voltage (Note 8) IOH = –2.5 mA 3.3 V min
No load 3.8 V min
Output low voltage (Note 8) IOL = 2.5 mA 1.1 V max
No load 0.6 V max
Note 8: SYNC is a Schmitt trigger input and is over-
current protected with a 1.5 kΩ series resistor.