DAN-139 Datasheet, PDF (4/5 Pages) Exar Corporation – EXAR’S XR16L580 COMPARED

DATA COMMUNICATIONS APPLICATION NOTE
DAN139
2.0 SUMMARY OF DIFFERENCES BETWEEN THE XR16L580 AND INDUSTRY STANDARD 16550
UART
The differences between the XR16L580 and most industry standard 16550 UARTs are summarized in the table
below.
TABLE 3: DIFFERENCES BETWEEN EXAR’S XR16L580 AND INDUSTRY STANDARD 16550
COMPARISON
XR16L580
STANDARD 16550
Data Bus Standard
Power Supply Operation
5V Tolerant Inputs
Max Frequency on XTAL1
BRG Prescaler
Package
Extra Pins Available in XR16L580
Extra Pins Available in 16550
Operating Temperature Ranges
TX/RX FIFO Size
TX/RX Trigger Tables
TX FIFO Interrupt Trigger Levels
RX FIFO Interrupt Trigger Levels
Wake-up Interrupt
Hardware Flow Control
Software Flow Control
Infrared Mode
Invert Infrared RX signal control
Sleep Mode
Low Power Mode
Diagnostic Modes
Intel or Motorola
2.5, 3.3 and 5 V
Yes
16 MHz @ 2.5V
32 MHz @ 3.3V
48 MHz @ 5V
1 or 4
32-QFN, 48-TQFP
16/68#, PwrSave
N/A
(RCLK is internally connected to Baudout)
Industrial
16
1 Trigger Table
4 Selectable
4 Selectable
Yes
Auto RTS/CTS Flow Control
Auto Xon/Xoff Flow Control
IrDA encoder/decoder (ver 1.0)
Yes
Sleep Mode with Auto Wake-up
Yes (Power-Save)
Local Loopback
Intel
3.3 and 5 V
No
16 MHz @ 3.3V
24 MHz @ 5V
1
44-PLCC, 48-TQFP, 40-PDIP
No
RCLK, CS0, CS1, Baudout, IOW, IOR,
DDIS, -TXRDY, -AS, -RXRDY,
-OP1, -OP2
Commercial and Industrial
16
1 Trigger Table
1
4 Selectable
No
No
No
No
No
No
No
Local Loopback
3.0 REPLACING THE INDUSTRY STANDARD 16550 UART WITH THE XR16L580 IN THE 48-TQFP
PACKAGE
The XR16L580 can be installed into any industry standard 16550 UART socket with no hardware changes
when using the 48-TQFP package under these conditions: crystal oscillator frequency of 1.8432 - 14.7456
MHz, the legacy signals in Table 1 are unused and the pads for the 16/68# and PwrSave pins have no connec-
tions.
The software will need to be updated to take advantage of the enhanced features in the XR16L580 that are not
available in the industry standard 16550 like Sleep Mode with Power-Save, Automatic RTS/CTS Hardware
Flow Control, Automatic Xon/Xoff Software Flow Control, and Infrared Mode.
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