External Clock Input/Output; Counter Section; Memory - Measurement Computing USB-1608FS User Manual

USB-1608FS User's Guide

External clock input/output

Parameter
Pin name
Pin type
Software selectable direction
Input clock rate
Clock pulse width
Input leakage current
Input high voltage
Input low voltage
Output high voltage (Note 4)
Output low voltage (Note 4)
SYNC is a Schmitt trigger input and is over-current protected with a 200 Ohm series resistor.
Note 4:

Counter section

Pin name (Note 5)
Counter type
Number of channels
Input type
Input source
Resolution
Schmidt trigger hysteresis
Input leakage current
Maximum input frequency
High pulse width
Low pulse width
Input high voltage
Input low voltage
CTR is a Schmitt trigger input protected with a 1.5K Ohm series resistor.
Note 5:

Memory

Data FIFO
EEPROM
EEPROM configuration
Table 7. External clock I/O specifications
Conditions
Output
Input
Input
Output
IOH = –2.5 mA
No load
IOL = 2.5 mA
No Load
Table 8. Counter specifications
CTR
Event counter
1
TTL, rising edge triggered
CTR screw terminal
32 bits
20 mV to 100 mV
±1µA
1 MHz
500 ns min
500 ns min
4.0 V min, 5.5 V absolute max
1.0 V max, –0.5 V absolute min
Table 9. Memory specifications
32,768 samples, 65,536 bytes
1,024 bytes
Address range
0x000-0x07F
0x080-0x1FF
0x200-0x3FF
4-3
Specification
SYNC
Bidirectional
Outputs internal A/D pacer clock.
Receives A/D pacer clock from external
source.
50 kHz, maximum
1µs min
5µs min
±1.0µA
4.0 V min, 5.5 V absolute max
1.0 V max, –0.5 V absolute min
3.3 V min
3.8 V min
1.1 V max
0.6 V max
Access Description
Reserved 128 bytes system data
Read/write 384 bytes cal data
Read/write 512 bytes user area
Specifications