17
Chapter 4
Specifications
Typical for 25 °C unless otherwise specified.
Specifications in
italic text
are guaranteed by design.
Digital input / output
Table 1. Digital I/O specifications
Digital type
82C55
Number of I/O
24 (Port A0 through Port C7)
Configuration
2 banks of 8 and 2 banks of 4, or
3 banks of 8
Pull up/pull-down configuration
All pins pulled up to Vs via 47K resistors (default). Selection available for
pull down to ground. Hardware selectable via zero ohm resistor.
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 (IOH = -2.5 mA)
0.4 V max
Power up / reset state
Input mode
Counter
Table 2. Counter specifications
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
Power
Table 3. Power specifications
Parameter Conditions
Specification
Supply current (Note 1)
20 mA typ, 40 mA max
Connected to Self-Powered Hub
4.5 V min, 5.25 V max
+5V USB power available (Note 2)
Connected to Bus-Powered Hub
4.1 V min, 5.25 V max
Connected to Self-Powered Hub
460 mA max
Output Current (Note 3)
Connected to Bus-Powered Hub
60 mA max
Note 1:
This is the total current requirement for the RedLab 1024LS which includes up to 5mA for the status
LED.
Содержание RedLab 1024LS
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