SC16C754IB80,551

UARTs (Universal Asynchronous Receiver Transmitter) Overview

The SC16C754IB80,551 is a quad universal asynchronous receiver/transmitter (UART) featuring 64-byte FIFOs for both transmit and receive channels. It supports data rates up to 5 Mbits/s at 3.3 V and 5 V operation, with a maximum of 3 Mbits/s at 2.5 V. The device includes automatic hardware and software flow control, programmable baud rate generation via a divisor between 1 and 65535, and an internal loop-back capability for diagnostics. It operates on an 8-bit peripheral bus with selectable character lengths of 5, 6, 7, or 8 bits, and supports even, odd, or no parity with 1, 1.5, or 2 stop bits. The component is housed in an LQFP80 plastic package.

UARTs (Universal Asynchronous Receiver Transmitter) Feature Summary

• Quad UART architecture with independent 64-byte transmit and receive FIFOs per channel
• Automatic hardware flow control using Auto-RTS and Auto-CTS signals to prevent overrun errors
• Programmable software flow control with configurable Xon/Xoff characters and interrupt capabilities
• Fully prioritized interrupt system with six distinct levels for efficient processor management

UARTs (Universal Asynchronous Receiver Transmitter) Applications

• High-speed serial communication interfaces requiring multiple independent channels
• Systems utilizing DMA transfers for reduced CPU overhead in data acquisition
• Modem control applications requiring full modem status signal monitoring (CTS, RTS, DSR, DTR, RI, CD)
• Embedded systems needing on-board diagnostic capabilities through internal loop-back modes

UARTs (Universal Asynchronous Receiver Transmitter) Procurement Notes

Verify the specific ordering suffix IB80 corresponds to the LQFP80 plastic low profile quad flat package with 80 leads. Confirm that the device meets the required voltage specifications for 3.3 V or 5 V operation, as performance varies with supply voltage. Ensure compatibility with the target system's address decoding logic, as individual channels are selected via CSA-CSD pins. Check for pin compatibility requirements if replacing older SC16C554 or SC16C654 variants.

UARTs (Universal Asynchronous Receiver Transmitter) Selection Notes

Select this component when four independent UART channels are required within a single integrated circuit. Consider the 64-byte FIFO depth for applications demanding high throughput or irregular data processing intervals. Evaluate the need for hardware versus software flow control based on system latency constraints. Verify that the available clock input can support the desired baud rate generator divisor range for precise timing requirements.

UARTs (Universal Asynchronous Receiver Transmitter) Part Context

The SC16C754 is part of the Philips Semiconductors UART family, designed as an enhanced successor to the SC16C554 and SC16C654. It maintains pin compatibility with these predecessors while adding features such as larger FIFOs and enhanced flow control registers. The IB80 variant specifically denotes the LQFP80 package option, distinguishing it from the PLCC68 version (IA68). This lineage ensures backward compatibility for designs migrating from earlier generations.

UARTs (Universal Asynchronous Receiver Transmitter) Replacement Considerations

SC16C654IA68

UARTs (Universal Asynchronous Receiver Transmitter) FAQ

How does the SC16C754 handle hardware flow control to prevent data loss?

The device uses Auto-RTS and Auto-CTS functions enabled via the Enhanced Feature Register. Auto-RTS deactivates when the RX FIFO reaches a halt trigger level and reasserts when it drops below a resume level. Auto-CTS prevents transmission until the CTS input is active, eliminating overrun errors.

What is the function of the CLKSEL pin during reset?

The CLKSEL pin selects between divide-by-1 or divide-by-4 prescalable clock inputs. During reset, a logic 1 latches a 0 into the Modem Control Register (MCR), selecting divide-by-1, while a logic 0 latches a 1, selecting divide-by-4. This value can be altered after reset by writing to the MCR.

Can the SC16C754 operate in DMA mode without processor intervention?

Yes, in DMA Mode 1, the device supports multi-character block transfers. The TXRDY and RXRDY signals indicate when trigger levels are reached, allowing DMA controllers to manage data movement directly between the FIFOs and memory without continuous CPU polling.