User's Manual

6 SPECIFICATIONS
Power Consumption
150 mA max +5V
Digital Input / Output
User installed. Dual footprint allows pull-up
or pull-down configuration
Pull-Up/Pull-Down Resistors
Input mode (high impedance)Power-up / reset state
0.8 volts max, −0.5 volts absolute min
Input Low
2.0 volts min, 5.5 volts absolute maxInput High
0.4 volts max @ 2.5mAOutput Low
3.0 volts min @ −2.5mA
Output High
• 2 banks of 8 and 2 banks of 4, or
• 3 banks of 8, or
2 banks of 8 with handshake
Configuration per 82C55
96Number of I/O
Four 82C55 Digital Type
Counter Section
Output:
Gate
Source:
Counter 3
- Not used
Output: Selectable Interrupt source
Gate: Tied to +5V
Source: Counter 1 OUT
Counter 2
Output: Selectable Interrupt source
Gate: Tied to +5V
Source: 2 MHz (crystal osc./8)
Counter 1
3 counters, 16 bits eachConfiguration
82C54Counter type
18