The SC16C554B/554DB is a 4-channel Universal Asynchronous Receiver and Transmitter (QUART) used for serial data communications. Its principal function is to convert parallel data into serial data and vice versa. The UART can handle serial data rates up to 5 Mbit/s. It comes with an Intel (16 mode) or Motorola (68 mode) interface.
The SC16C554B/554DB is pin compatible with the ST16C554 and TL16C554 and it will power-up to be functionally equivalent to the 16C454. Programming of control registers enables the added features of the SC16C554B/554DB. Some of these added features are the 16-byte receive and transmit FIFOs, four receive trigger levels. The SC16C554B/554DB also provides DMA mode data transfers through FIFO trigger levels and the TXRDY and RXRDY signals. (TXRDY and RXRDY signals are not available in the HVQFN48 package.) On-board status registers provide the user with error indications, operational status, and modem interface control. System interrupts may be tailored to meet user requirements. An internal loopback capability allows on-board diagnostics.
The SC16C554B/554DB operates at 5 V, 3.3 V and 2.5 V, and the industrial temperature range, and is available in plastic PLCC68, LQFP64, LQFP80, and HVQFN48 packages. On the HVQFN48 package only, channel C has all the modem pins. Channels A and B have only RTSn and CTSn pins and channel D does not have any modem pin.
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## Features
* 4 channel UART
* 5 V, 3.3 V and 2.5 V operation
* Industrial temperature range (-40 ℃ to +85 ℃)
* The SC16C554B is pin and software compatible with the industry-standard ST16C454/554, ST68C454/554, ST16C554, TL16C554
* The SC16C554DB is pin and software compatible with ST16C554D, and software compatible with ST16C454/554, ST16C554, TL16C554
* Up to 5 Mbit/s data rate at 5 V and 3.3 V, and 3 Mbit/s at 2.5 V
* 5 V tolerant on input only pins
* 16-byte transmit FIFO
* 16-byte receive FIFO with error flags
* Programmable auto-RTS and auto-CTS
* In auto-CTS mode, CTS controls transmitter
* In auto-RTS mode, RX FIFO contents and threshold control RTS
* Automatic hardware flow control (RTS/CTS)
* Software selectable baud rate generator
* Four selectable Receive FIFO interrupt trigger levels
* Standard modem interface
* Standard asynchronous error and framing bits (Start, Stop, and Parity Overrun Break)
* Transmit, Receive, Line Status, and Data Set interrupts independently controlled
* Fully programmable character formatting:
* 5-bit, 6-bit, 7-bit, or 8-bit characters
* Even, odd, or no-parity formats
* 1, 112, or 2-stop bit
* Baud generation (DC to 5 Mbit/s)
* False start-bit detection
* Complete status reporting capabilities
* 3-state output 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
* Prioritized interrupt system controls
* Modem control functions (CTS, RTS, DSR, DTR, RI, CD).
