Universal asynchronous receiver-transmitter
UART models

Universal asynchronous receiver-transmitter

Section Title: UART models
Table Section Text: None

Model	Description

WD1402A	The first single-chip UART on general sale. Introduced about 1971.

Exar XR21V1410

SIG60	DC-BUS UART communication over DC power lines up to 115.2 kbit/s, originally by Yamar Electronics

Intersil 6402

CDP 1854 (RCA, now Intersil)

Zilog Z8440	Universal synchronous and asynchronous receiver-transmitter. 2000 kbit/s.

Z8530/Z85C30	This universal synchronous and asynchronous receiver-transmitter has a 3-byte receive buffer and a 1-byte transmit buffer. It has hardware to accelerate the processing of HDLC and SDLC.

8250	Obsolete with 1-byte buffers. These UARTs' maximum standard serial port speed is 9600 bits per second if the operating system has a 1 millisecond interrupt latency.

8251

Motorola 6850

6551

Rockwell 65C52

16450

82510	This UART allows asynchronous operation up to 288 kbit/s, with two independent four-byte FIFOs. It was produced by Intel at least from 1993 to 1996, and Innovastic Semiconductor has a 2011 Data Sheet for IA82510.

16550	This UART's FIFO is broken, so it cannot safely run any faster than the 16450 UART. The 16550A and later versions fix this bug.

16550A	This UART has 16-byte FIFO buffers. Its receive interrupt trigger levels can be set to 1, 4, 8, or 14 characters.

16C552

16650	This UART was introduced by Startech Semiconductor which is now owned by Exar Corporation and is not related to Startech.com. Early versions have a broken FIFO buffer and therefore cannot safely run any faster than the 16450 UART.

16750	64-byte buffers. This UART can handle a maximum standard serial port speed of 460.8 kbit/s if the maximum interrupt latency is 1 millisecond.

16850	128-byte buffers. This UART can handle a maximum standard serial port speed of 921.6 kbit/s if the maximum interrupt latency is 1 millisecond.

16C850

16950	128-byte buffers. This UART can handle a maximum standard serial port speed of 921.6 kbit/s if the maximum interrupt latency is 1 millisecond.

16C950

16954	Quad-port version of the 16950/16C950. 128-byte buffers.

16C954

16C1550/16C1551	UART with 16-byte FIFO buffers. Up to 1.5 Mbit/s.

16C2450	Dual UART with 1-byte FIFO buffers.

16C2550	Dual UART with 16-byte FIFO buffers. Pin-to-pin and functional compatible to 16C2450. Software compatible with INS8250 and NS16C550.

SCC2691	Currently produced by NXP, the 2691 is a single channel UART that also includes a programmable counter/timer. The 2691 has a single-byte transmitter holding register and a 4-byte receive FIFO.

SCC28L91

SCC2692	Currently produced by NXP, these devices are dual UARTs (DUART), consisting of two communications channels, associated control registers and one counter/timer.

SC26C92

SC28L92

SCC28C94	Currently produced by NXP, the 28C94 quadruple UART (QUART) is functionally similar to a pair of SCC26C92 DUARTs mounted in a common package, with the addition of an arbitrated interrupt system for efficient processing during periods of intense channel activity.

SCC2698B	Currently produced by NXP, the 2698 octal UART (OCTART) is essentially four SCC2692 DUARTs in a single package. Specifications are the same as the SCC2692 (not the SCC26C92).

SCC28L198	Currently produced by NXP, the 28L198 OCTART is essentially an upscaled enhancement of the SCC28C94 QUART described above, with eight independent communications channels, as well as an arbitrated interrupt system for efficient processing during periods of intense channel activity.

Z85230	Synchronous/Asynchronous modes, 2 ports. Provides signals needed by a third party DMA controller needed to perform DMA transfers.

Hayes ESP	1 KB buffers, 921.6 kbit/s, 8-ports.

Exar XR17V352, XR17V354 and XR17V358	Dual, Quad and Octal PCI Express UARTs with 16550 compatible register Set, 256-byte TX and RX FIFOs, Programmable TX and RX Trigger Levels, TX/RX FIFO Level Counters, Fractional baud rate generator, Automatic RTS/CTS or DTR/DSR hardware flow control with programmable hysteresis, Automatic Xon/Xoff software flow control, RS-485 half duplex direction control output with programmable turn-around delay, Multi-drop with Auto Address Detection, Infrared (IrDA 1.1) data encoder/decoder.

Exar XR17D152, XR17D154 and XR17D158	Dual, Quad and Octal PCI bus UARTs with 16C550 Compatible 5G Register Set, 64-byte Transmit and Receive FIFOs, Transmit and Receive FIFO Level Counters, Programmable TX and RX FIFO Trigger Level, Automatic RTS/CTS or DTR/DSR Flow Control, Automatic Xon/Xoff Software Flow Control, RS485 HDX Control Output with Selectable Turn-around Delay, Infrared (IrDA 1.0) Data Encoder/Decoder, Programmable Data Rate with Prescaler, Up to 6.25 Mbit/s Serial Data Rate.

Exar XR17C152, XR17C154 and XR17C158	Dual, Quad and Octal 5 V PCI bus UARTs with 16C550 Compatible Registers, 64-byte Transmit and Receive FIFOs, Transmit and Receive FIFO Level Counters, Automatic RTS/CTS or DTR/DSR Flow Control, Automatic Xon/Xoff Software Flow Control, RS485 Half-duplex Control with Selectable Delay, Infrared (IrDA 1.0) Data Encoder/Decoder, Programmable Data Rate with Prescaler, Up to 6.25 Mbit/s Serial Data Rate.

Exar XR17V252, XR17V254 and XR17V258	Dual, Quad and Octal 66 MHz PCI bus UARTs with Power Management Support, 16C550 compatible register set, 64-byte TX and RX FIFOs with level counters and programmable trigger levels, Fractional baud rate generator, Automatic RTS/CTS or DTR/DSR hardware flow control with programmable hysteresis, Automatic Xon/Xoff software flow control, RS-485 half duplex direction control output with selectable turn-around delay, Infrared (IrDA 1.0) data encoder/decoder, Programmable data rate with prescaler.

Sentence(s)

The 16550 has a 16-byte FIFO.

final_sentence: The 16550 has a 16-byte FIFO.