XR21B1420IL28-0A Datasheet, PDF (6/60 Pages) Exar Corporation – Enhanced 1-Ch Full-Speed USB UART

Functional Block Diagram
VBUS_SENSE
USBD+
USBD-
RESET#
VCC
VCC_REG
GND
Internal
Oscillator
(48MHz)
USB Slave Interface
USB
Descriptors
OTP
Fractional
BRG
512-byte
TX FIFO
512-byte
RX FIFO
Internal
Status and
Control
Registers
GPIOs/
Modem IO
UART
LDO
3V3
XR21B1420
TX
RX
GPIO9/RXT
GPIO8/TXT
GPIO7/RS485
GPIO6/CLK
GPIO5/RTS#/RS485
GPIO4/CTS#
GPIO3/DTR#
GPIO2/DSR#
GPIO1/CD#
GPIO0/RI#/RWK#
USB_STAT1
USB_STAT2
© 2014 Exar Corporation
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exar.com/XR21B1420
Rev 1A