XR21V1414
4-CH FULL-SPEED USB UART
SEPTEMBER 2010
REV. 1.1.0
GENERAL DESCRIPTION
The XR21V1414 (V1414) is an enhanced 4-channel
USB Universal Asynchronous Receiver and
Transmitter (UART). The USB interface is fully
compliant to Full Speed USB 2.0 specification that
supports 12 Mbps USB data transfer rate. The USB
interface also supports USB suspend, resume and
remote wakeup operations.
The V1414 operates from an internal 48MHz clock
therefore no external crystal/oscillator is required like
previous generation UARTs. With the fractional baud
rate generator, any baud rate can accurately be
generated using the internal 48MHz clock.
The large 128-byte TX FIFO and 384-byte RX FIFO
of the V1414 helps to optimize the overall data
throughput for various applications. The Automatic
Transceiver Direction control feature simplifies both
the hardware and software for half-duplex RS-485
applications. If required, the multidrop (9-bit) mode
with automatic half-duplex transceiver control feature
further
simplifies
typical
multidrop
RS-485
applications.
The V1414 operates from a single 2.97 to 3.63 volt
power supply and has 5V tolerant inputs. The V1414
is available in a 48-pin TQFP package.
WHQL certified software drivers for Windows 2000,
XP, Vista, 7, and CE, as well as Linux and Mac are
supported for the XR21V1414.
APPLICATIONS
FEATURES
•
USB 2.0 Compliant, Full-speed (12 Mbps)
s
Supports USB suspend, resume and remote
wakeup operations
Data rates up to 12 Mbps
Fractional Baud Rate Generator
128 byte TX FIFO
384 byte RX FIFO
7, 8 or 9 data bits
1 or 2 stop bits
Odd, even, mark, space, or no parity
Automatic Hardware (RTS/CTS or DTR/DSR)
Flow Control
Automatic Software (Xon/Xoff) Flow Control
Multidrop mode
Auto Transceiver Enable
Half-Duplex mode
Selectable GPIO or Modem I/O
•
Enhanced Features of each UART
s
s
s
s
s
s
s
s
s
s
s
s
s
•
Internal 48 MHz clock
•
Single 2.97-3.63V power supply
•
5V tolerant inputs
•
48-pin TQFP package
•
Virtual COM Port WHQL certified drivers
s
s
s
s
Windows 2000, XP Vista and 7
Windows CE 4.2, 5.0, 6.0
Linux
Mac
•
Portable Appliances
•
External Converters (dongles)
•
Battery-Operated Devices
•
Cellular Data Devices
•
Factory Automation and Process Controls
•
Industrial applications
Exar
Corporation 48720 Kato Road, Fremont CA, 94538
•
(510) 668-7000
•
FAX (510) 668-7017
•
www.exar.com
XR21V1414
4-CH FULL-SPEED USB UART
F
IGURE
1. XR21V1414 B
LOCK
D
IAGRAM
REV. 1.1.0
3.3V VCC
GND
Fractional
BRG
128-byte
TX FIFO
384-byte
RX FIFO
TXA
RXA
GPIOA5/RTSA#
GPIOA4/CTSA#
GPIOA3/DTRA#
GPIOA2/DSRA#
GPIOA1/CDA#
GPIOA0/RIA#
Internal
Status and
Control
Registers
USBD+
USBD-
USB Slave
Interface
GPIOs/
Modem IO
UART Channel A
TXB
RXB
GPIOB[5:0]/ModemIO
UART Channel B
(Same as Ch A)
SDA
SCL
I
2
C
Interface
UART Channel C
(Same as Ch A)
TXC
RXC
GPIOC[5:0]/ModemIO
TXD
RXD
GPIOD[5:0]/ModemIO
Internal
48MHz
Oscillator
UART Channel D
(Same as Ch A)
2
XR21V1414
REV. 1.1.0
4-CH FULL-SPEED USB UART
F
IGURE
2. P
IN
O
UT
A
SSIGNMENT
GPIOD0/RID#
TXD
RXD
GND
GND
USBD-
USBD+
VCC
VCC
GPIOD5/RTSD#
GPIOD4/CTSD#
GPIOD3/DTRD#
36 35 34 33 32 31 30 29 28 27 26 25
24
37
38
39
40
41
42
43
44
45
46
47
48
1 2
3
4
5
6
7
8
23
22
21
20
19
18
17
16
15
14
13
9 10 11 12
SCL
SDA
GPIOD1/CDD#
VCC
GND
RXA
TXA
GPIOC0/RIC#
GPIOC1/CDC#
GPIOC2/DSRC#
GPIOC3/DTRC#
GPIOC4/CTSC#
XR21V1414
48-TQFP
GPIOC5/RTSC#
RXC
TXC
GPIOA0/RIA#
GPIOA1/CDA#
GND
VCC
GPIOA2/DSRA#
GPIOA3/DTRA#
GPIOB0/RIB#
GPIOB1/CDB#
GPIOB2/DSRB#
ORDERING INFORMATION
P
ART
N
UMBER
XR21V1414IM48
P
ACKAGE
48-pin TQFP
O
PERATING
T
EMPERATURE
R
ANGE
-40° to +85°
C
C
D
EVICE
S
TATUS
Active
GND
LOWPOWER
GPIOD2/DSRD#
GND
VCC
GPIOA5/RTSA#
GPIOA4/CTSA#
TXB
RXB
GPIOB5/RTSB#
GPIOB4/CTSB#
GPIOB3/DTRB#
3
XR21V1414
4-CH FULL-SPEED USB UART
REV. 1.1.0
PIN DESCRIPTIONS
Pin Description
N
AME
48-QFN
P
IN
#
T
YPE
D
ESCRIPTION
UART Channel A Signals
RXA
31
I
UART Channel A Receive Data or IR Receive Data. This pin has an inter-
nal pull-up resistor. Internal pull-up resistor is not disabled during suspend
mode.
UART Channel A Transmit Data or IR Transmit Data.
UART Channel A general purpose I/O or UART Ring-Indicator input
(active low) or Remote Wakeup Input (
See ”Section 1.5.11, Remote
Wakeup” on page 14.
). This pin has an internal pull-up resistor which
is disabled during suspend mode. If using this GPIO as an input, an exter-
nal pull-up resistor is required to minimize the power consumption in the
suspend mode.
UART Channel A general purpose I/O or UART Carrier-Detect input
(active low). This pin has an internal pull-up resistor which is disabled dur-
ing suspend mode. If using this GPIO as an input, an external pull-up
resistor is required to minimize the power consumption in the suspend
mode.
UART Channel A general purpose I/O or UART Data-Set-Ready input
(active low).
See ”Section 1.5.5, Automatic DTR/DSR Hardware
Flow Control” on page 13.
This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an
external pull-up resistor is required to minimize the power consumption in
the suspend mode.
UART Channel A general purpose I/O or UART Data-Terminal-Ready out-
put (active low).
See ”Section 1.5.5, Automatic DTR/DSR Hard-
ware Flow Control” on page 13.
This pin has an internal pull-up
resistor which is disabled during suspend mode. If using this GPIO as an
input, an external pull-up resistor is required to minimize the power con-
sumption in the suspend mode.
UART Channel A general purpose I/O or UART Clear-to-Send input
(active low).
See ”Section 1.5.4, Automatic RTS/CTS Hardware
Flow Control” on page 12.
This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an
external pull-up resistor is required to minimize the power consumption in
the suspend mode.
UART Channel A general purpose I/O or UART Request-to-Send output
(active low).
See ”Section 1.5.4, Automatic RTS/CTS Hardware
Flow Control” on page 12.
This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an
external pull-up resistor is required to minimize the power consumption in
the suspend mode.
TXA
GPIOA0/RIA#
30
21
O
I/O
GPIOA1/CDA#
20
I/O
GPIOA2/DSRA#
17
I/O
GPIOA3/DTRA#
16
I/O
GPIOA4/CTSA#
7
I/O
GPIOA5/RTSA#
6
I/O
UART Channel B Signals
RXB
9
I
UART Channel B Receive Data or IR Receive Data. This pin has an inter-
nal pull-up resistor. Internal pull-up resistor is not disabled during suspend
mode.
4
XR21V1414
REV. 1.1.0
4-CH FULL-SPEED USB UART
Pin Description
N
AME
TXB
GPIOB0/RIB#
48-QFN
P
IN
#
8
15
T
YPE
O
I/O
D
ESCRIPTION
UART Channel B Transmit Data or IR Transmit Data.
UART Channel B general purpose I/O or UART Ring-Indicator input
(active low). This pin has an internal pull-up resistor which is disabled dur-
ing suspend mode. If using this GPIO as an input, an external pull-up
resistor is required to minimize the power consumption in the suspend
mode.
UART Channel B general purpose I/O or UART Carrier-Detect input
(active low). This pin has an internal pull-up resistor which is disabled dur-
ing suspend mode. If using this GPIO as an input, an external pull-up
resistor is required to minimize the power consumption in the suspend
mode.
UART Channel B general purpose I/O or UART Data-Set-Ready input
(active low).
See ”Section 1.5.5, Automatic DTR/DSR Hardware
Flow Control” on page 13.
This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an
external pull-up resistor is required to minimize the power consumption in
the suspend mode.
UART Channel B general purpose I/O or UART Data-Terminal-Ready out-
put (active low).
See ”Section 1.5.5, Automatic DTR/DSR Hard-
ware Flow Control” on page 13.
This pin has an internal pull-up
resistor which is disabled during suspend mode. If using this GPIO as an
input, an external pull-up resistor is required to minimize the power con-
sumption in the suspend mode.
UART Channel B general purpose I/O or UART Clear-to-Send input
(active low).
See ”Section 1.5.4, Automatic RTS/CTS Hardware
Flow Control” on page 12.
This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an
external pull-up resistor is required to minimize the power consumption in
the suspend mode.
UART Channel B general purpose I/O or UART Request-to-Send output
(active low).
See ”Section 1.5.4, Automatic RTS/CTS Hardware
Flow Control” on page 12.
This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an
external pull-up resistor is required to minimize the power consumption in
the suspend mode.
GPIOB1/CDB#
14
I/O
GPIOB2/DSRB#
13
I/O
GPIOB3/DTRB#
12
I/O
GPIOB4/CTSB#
11
I/O
GPIOB5/RTSB#
10
I/O
UART Channel C Signals
RXC
23
I
UART Channel C Receive Data or IR Receive Data. This pin has an inter-
nal pull-up resistor. Internal pull-up resistor is not disabled during suspend
mode.
UART Channel C Transmit Data or IR Transmit Data.
UART Channel C general purpose I/O or UART Ring-Indicator input
(active low). This pin has an internal pull-up resistor which is disabled dur-
ing suspend mode. If using this GPIO as an input, an external pull-up
resistor is required to minimize the power consumption in the suspend
mode.
TXC
GPIOC0/RIC#
22
29
O
I/O
5
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