TL16C550AFN

异步通信部件 ASYNCHRONOUS COMMUNICATIONS ELEMENT

description

The TL16C550A is a functional upgrade of the TL16C450 asynchronous communications element ACE. Functionally identical to the TL16C450 on power up character mode†, the TL16C550A can be placed in an alternate mode FIFO to relieve the CPU of excessive software overhead.

In this mode, internal FIFOs are activated allowing 16 bytes plus 3 bits of error data per byte in the receiver FIFO to be stored in both receive and transmit modes. To minimize system overhead and maximize system efficiency, all logic is on the chip. Two of the TL16C450 terminal functions terminals 24 and 29 on the N package and terminals 27 and 32 on the FN package have been changed to allow signalling of direct memory address DMA transfers.

Capable of Running With All Existing TL16C450 Software

After Reset, All Registers Are Identical to the TL16C450 Register Set

In the FIFO Mode, Transmitter and Receiver Are Each Buffered With 16-Byte FIFOs to Reduce the Number of Interrupts to the CPU

In the TL16C450 Mode, Holding and Shift Registers Eliminate the Need for Precise Synchronization Between the CPU and Serial Data

Programmable Baud Rate Generator Allows Division of Any Input Reference Clock by 1 to 216–1 and Generates an Internal 16×Clock

Standard Asynchronous Communication Bits Start, Stop, and Parity Added to or Deleted From the Serial Data Stream

Independent Receiver Clock Input

Transmit, Receive, Line Status, and Data Set Interrupts Independently Controlled

Fully Programmable Serial Interface Characteristics:

– 5-, 6-, 7-, or 8-Bit Characters

– Even-, Odd-, or No-Parity Bit Generation and Detection

– 1-, 1 1/2-, or 2-Stop Bit Generation

– Baud Generation dc to 256 Kbit/s

False-Start Bit Detection

Complete Status Reporting Capabilities

3-State TTL Drive Capabilities for

Bidirectional Data Bus and Control Bus

Line Break Generation and Detection

Internal Diagnostic Capabilities:

– Loopback Controls for Communications Link Fault Isolation

– Break, Parity, Overrun, Framing Error Simulation

Fully Prioritized Interrupt System Controls

Modem Control Functions CTS, RTS, DSR, DTR, RI, and DCD

Faster Plug-In Replacement for National Semiconductor NS16550A