XR16L651 Datasheet, PDF (1/56 Pages) Exar Corporation – 2.25V TO 5.5V UART WITH 32-BYTE FIFO

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JANUARY 2004
GENERAL DESCRIPTION
The XR16L651¹ (651) is a 2.25 to 5.5 volt Universal
Asynchronous Receiver and Transmitter (UART) with
5 volt tolerant inputs. This device supports Intel and
Motorola data bus interfaces and is software
compatible to industry standard 16C450, 16C550,
ST16C580 and ST16C650A UARTs.
The 651 has 32 bytes of TX and RX FIFOs and is
capable of operating up to serial data rates of 3.125
Mbps at 5 volt supply voltage. The internal registers
include the 16C550 register set plus Exar’s enhanced
registers for additional features to support today’s
highly demanding data communication needs. The
enhanced features include automatic hardware and
software flow control, selectable TX and RX trigger
levels, and wireless infrared (IrDA) encoder/decoder.
The device provides a new capability to give user the
ability to program the wireless infrared encoder
output pulse width, hence reducing the power
consumption of a handheld unit.
The XR16L651 device comes in a small 7x7x1mm
48-pin TQFP package in both the commercial and
industrial temperature ranges.
NOTE: 1 Covered by US patents #5,649,122.
XR16L651
2.25V TO 5.5V UART WITH 32-BYTE FIFO
FEATURES
REV. 1.3.0
Added feature in devices with top mark date code of
"C2 YYWW" and newer:
s 0 ns address hold time
• 2.25 to 5.5 Volt Operation w/ 5 Volt Tolerant Inputs
• ST16C450/550/580/650A Software Compatible
• Intel, Motorola or PC Mode 8-bit Bus Interface
• Up to 3.125 Mbps Data Rate at 5 Volt Operation
• 32-byte Transmit and Receive FIFOs
• Automatic RS485 Half-Duplex Control Output
• Automatic Hardware (RTS/CTS) Flow Control
• Hardware Flow Control Hysteresis
• Automatic Software (Xon/Xoff) Flow Control
• Infrared (IrDA) Encoder/Decoder Enable Input
• Programmable Infrared Encoder Pulse Width
• Sleep Mode with Wake-up Indicator via interrupt
APPLICATIONS
• Battery Operated Electronics
• Internet Appliances
• Handheld Terminal
• Personal Digital Assistants
• Cellular Phones DataPort
• Wireless Infrared Data Communications Systems
FIGURE 1. BLOCK DIAGRAM
RESET
A2:A0
D7:D0
IOR#
IOR
IOW#/R/W#
IOW
CS2#
CS1
CS0
INT
TXRDY#
RDRDY#
DDIS#
ENIR
IM#
PCMODE#
S1
S2
S3
IRQA
IRQB
IRQC
Intel,
Motorola
or PC
Data Bus
Interface
PC Mode:
COM 1 to 4
Decode Logic
UART
Configuration
Regs
BRG
Prescaler
32 Byte TX FIFO
Transmitter
Infrared Encoder and
Pulse Width Control
CTS Flow
Control
Modem Control Signals
RTS Flow
Control
Infrared
Decoder
Receiver with Auto
Software Flow Control
32 Byte RX FIFO
Baud Rate Generator
Crystal Osc/Buffer
TX
DTR#, DSR#,
RTS#, CTS#,
CD#, RI#
RX
XTAL1/CLK
XTAL2
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com