Measurement Computing PC104-DAS08 - Manual (Page 20)

Digital Input / Output
Digital Type (Main connector)
Output: 74LS273
Input: 74LS244
Configuration 4 fixed output bits, 3 fixed input bits
Number of channels 4 out, 3 in
Output High 2.7 volts min @
−
0.4 mA
Output Low 0.4 volts max @ 8 mA
Input High 2.0 volts min, 7 volts absolute max
Input Low 0.8 volts max,
−
0.5 volts absolute min
Output power-up / reset state
Interrupts 2 thru 7, jumper-selectable
Interrupt enable Programmable
Interrupt sources External (Interrupt In), rising edge
Counter Section
Counter type 82C54
Configuration 3 down-counters, 16 bits each
Counter 0 - independent, user configurable
Source: user connector (Counter 0 In)
Gate: user connector (Gate 0)
Output: user connector (Counter 0 Out)
Counter 1 - independent, user configurable
Source: user connector (Counter 1 In)
Gate: user connector (Gate 1)
Output: user connector (Counter 1 Out)
Counter 2 - independent, user configurable
Source: PC SysClk via divide by 2 circuit
Gate: user connector (Gate 2)
Output: user connector (Counter 2 Out)
Clock input frequency 10 MHz max
High pulse width (clock input) 30 ns min
Low pulse width (clock input) 50 ns min
Gate width high 50 ns min
Gate width low 50 ns min
Input low voltage 0.8V max
Input high voltage 2.0V min
Output low voltage 0.4V max
Output high voltage 3.0V min
Environmental
Operating temperature range 0 to 50°C
Storage temperature range
−
20 to 70°C
Humidity 0 to 90% non-condensing
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