NTE3882
Integrated Circuit
NMOS, Counter Timer Control (CTC)
Description:
The NTE3882 Counter Timer Circuit (CTC) is a programmable, four channel device in a 28鈥揕ead DIP
type package that provides counting and timing functions for the NTE3880. The NTE3880 configures
the NTE3882鈥檚 four independent channels to operate under various modes and conditions as
required.
The internal structure of the NTE3882 consists of an NTE3880 bus interface, internal control logic,
four counter channels, and interrupt control logic. Each channel has an interrupt vector for automatic
interrupt vectoring, and interrupt priority is determined by channel number with channel
鈭?/div>
having the
highest priority.
The channel logic is composed of 2 registers, 2 counters and control logic. The registers include and
8鈥揵it time constant register and an 8鈥揵it channel control register. The counters include as 8鈥揵it read-
able down counter and an 8鈥揵it prescaler. The prescaler may be programmed to divide the system
clock by either 16 or 256.
Structure:
D
N鈥揅hannel Silicon Gate Depletion Load Technology
D
Single 5V Supply
D
Single Phase 5V Clock
D
Four Independent Programmable 8鈥揃it Counter/16鈥揃it Timer Channels
Features:
D
Each Channel may be Selected to Operate in Either a Counter Mode or Timer Mode
D
Programmable Interrupts on Counter or Timer States
D
A Time Constant Register Automatically Reloads, the Down Counter at Zero and the Cycle is
Repeated
D
Readable Down Counter Indicates Number of Counts鈥搕o鈥揋o until Zero
D
Selectable 16 or 256 Clock Prescaler for Each Timer Channel
D
Selectable Positive or Negative Trigger may Initiate Timer Operation
D
Three Channels have Zero Count/Timeout Outputs capable of Driving Darlington Transistors
D
Daisy Chain Priority Interrupt Logic Included to Provide for Automatic Interrupt Vectoring without
External Logic
D
All Inputs and Outputs Fully TTL Compatible
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