XR21B1422IL40-0A Datasheet, PDF (8/60 Pages) Exar Corporation – Enhanced 2-Ch Full-Speed USB UART

Functional Block Diagram
VBUS_SENSE
USBD+
USBD-
RESET#
VCC
VCC_REG
GND
Internal
O scilla to r
(4 8 M H z)
USB Slave Interface
USB
D e scrip to rs
OTP
F ra c tio n a l
BRG
512-byte
TX FIFO
512-byte
RX FIFO
Internal
Status and
C o n tro l
R e g iste rs
G P IO s /
Modem IO
LDO
3V3
UART Ch A
UART Ch B
(same as Ch A)
XR21B1422
VIO
TXA
RXA
G P IO A 9/R X T A
G P IO A 8/T X T A
G P IO A 7/X E N A
G P IO A 6/C L K A
G P IO A 5/R T S A # /X E N A
G P IO A 4/C T S A #
G P IO A 3/D T R A #
G P IO A 2/D S R A #
G P IO A 1/C D A #
G P IO A 0 /R IA #
TXB
RXB
G P IO B [9 -0 ]
USB_STAT1
USB_STAT2
© 2014 Exar Corporation
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exar.com/XR21B1422
Rev 1A