SCC2681AE1A44数据手册恩XP中文资料规格书

描述 Description

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The Philips Semiconductors SCC2681 Dual Universal Asynchronous Receiver/Transmitter (DUART) is a single-chip MOS-LSI communications device that provides two independent full-duplex asynchronous receiver/transmitter channels in a single package. It interfaces directly with microprocessors and may be used in a polled or interrupt driven system. It is manufactured in a CMOS process.
The operating mode and data format of each channel can be programmed independently. Additionally, each receiver and transmitter can select its operating speed as one of eighteen fixed baud rates, a 16× clock derived from a programmable counter/timer, or an external 1× or 16× clock. The baud rate generator and counter/timer can operate directly from a crystal or from external clock inputs. The ability to independently program the operating speed of the receiver and transmitter make the DUART particularly attractive for dual-speed channel applications such as clustered terminal systems.
Each receiver is quadruply buffered to minimize the potential of receiver over-run or to reduce interrupt overhead in interrupt driven systems. In addition, a flow control capability is provided to disable a remote DUART transmitter when the buffer of the receiving device is full.
Also provided on the SCC2681 are a multipurpose 7-bit input port and a multipurpose 8-bit output port. These can be used as general purpose I/O ports or can be assigned specific functions (such as clock inputs or status/interrupt outputs) under program control.
The SCC2681 is available in three package versions: 40-pin and 28-pin DIPs (both 0.6? wide); and a 44-pin PLCC.

特性 Features

Dual full-duplex asynchronous receiver/transmitter
Quadruple buffered receiver data registers
Programmable data format 5 to 8 data bits plus parity
Odd, even, no parity or force parity
1, 1.5 or 2 stop bits programmable in 1/16-bit increments
Programmable baud rate for each receiver and transmitter selectable from: 22 fixed rates: 50 to 115.2 k baud
16-bit programmable Counter/Timer Non-standard rates to 115.2 kb
One user-defined rate derived from programmable timer/counter
External 1× or 16× clock
Parity, framing, and overrun error detection
False start bit detection
Line break detection and generation
Programmable channel mode Normal (full-duplex)
Automatic echo
Local loopback
Remote loopback
Multi-function programmable 16-bit counter/timer
Multi-function 7-bit input port Can serve as clock or control inputs
Change of state detection on four inputs
100 kΩ typical pull-up resistor
Multi-function 8-bit output port Individual bit set/reset capability
Outputs can be programmed to be status/interrupt signals
DMA signals
Auto 485 turn-around
Versatile interrupt system Single interrupt output with eight maskable interrupting conditions
Output port can be configured to provide a total of up to six separate wire-ORable interrupt outputs
Maximum data transfer: 1× ? 1 MB/sec; 16× ? 125 kB/sec
Automatic wake-up mode for multidrop applications
Start-end break interrupt/status
Detects break which originates in the middle of a character
On-chip crystal oscillator
Single +5 V power supply
Commercial and industrial temperature ranges available
DIP and PLCC packages