ST16C654 Pin Compatible With Additional
Enhancements
Supports Up To 24-MHz Crystal Input Clock
( 1.5 Mbps)
Supports Up To 48-MHz Oscillator Input
Clock ( 3 Mbps) for 5-V Operation
Supports Up To 32-MHz Oscillator Input
Clock ( 2 Mbps) for 3.3-V Operation
64-Byte Transmit FIFO
64-Byte Receive FIFO With Error Flags
Programmable and Selectable Transmit and
Receive FIFO Trigger Levels for DMA and
Interrupt Generation
Programmable Receive FIFO Trigger Levels
for Software/Hardware Flow Control
Software/Hardware Flow Control
− Programmable Xon/Xoff Characters
− Programmable Auto-RTS and Auto-CTS
Optional Data Flow Resume by Xon Any
Character
DMA Signalling Capability for Both
Received and Transmitted Data
Supports 3.3-V or 5-V Supply
Characterized for Operation From −40°C to
85°C
Software Selectable Baud Rate Generator
Prescalable Provides Additional Divide by 4
Function
Fast Access 2 Clock Cycle IOR/IOW Pulse
Width
Programmable Sleep Mode
Programmable Serial Interface
Characteristics
− 5, 6, 7, or 8-Bit Characters
− Even, Odd, or No Parity Bit Generation
and Detection
− 1, 1.5, or 2 Stop Bit Generation
False Start Bit Detection
Complete Status Reporting Capabilities in
Both Normal and Sleep Mode
Line Break Generation and Detection
Internal Test and Loopback Capabilities
Fully Prioritized Interrupt System Controls
Modem Control Functions (CTS, RTS, DSR,
DTR, RI, and CD)

description
The TL16C754B is a quad universal asynchronous receiver/transmitter (UART) with 64-byte FIFOs, automatic
hardware/software flow control, and data rates up to 3 Mbps. The TL16C754B offers enhanced features. It has
a transmission control register (TCR) that stores received FIFO threshold level to start/stop transmission during
hardware and software flow control. With the FIFO RDY register, the software gets the status of TXRDY/RXRDY
for all four ports in one access. On-chip 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 onboard diagnostics.
The UART transmits data sent to it from the peripheral 8-bit bus on the TX signal and receives characters on
the RX signal. Characters can be programmed to be 5, 6, 7, or 8 bits. The UART has a 64-byte receive FIFO
and transmit FIFO and can be programmed to interrupt at different trigger levels. The UART generates its own
desired baud rate based upon a programmable divisor and its input clock. It can transmit even, odd, or no parity
and 1, 1.5, or 2 stop bits. The receiver can detect break, idle or framing errors, FIFO overflow, and parity errors.
The transmitter can detect FIFO underflow. The UART also contains a software interface for modem control
operations, and software flow control and hardware flow control capabilities.
The TL16C754B is available in 80-pin TQFP and 68-pin PLCC packages.