herunterladen
1
REV. 1.0.0
XR21B1411_SP337 EVALUATION BOARD USER’S MANUAL
1.0 INTRODUCTION
This user’s manual is for the XR21B1411_SP337 evaluation board rev 1.2. The XR21B1411 will be configured
for the RS-232 mode when it is shipped from the factory. However, this manual describes how the evaluation
board can be re-configured to operate in different modes.
2.0 EVALUATION BOARD OVERVIEW
A block diagram of the evaluation board is shown in Figure 1 below..
The primary devices on the XR21B1411 evaluation board are all Exar devices.
•
The XR21B1411 is an enhanced 1-ch USB UART that can be powered directly from the 5V from VBUS.
•
The SP6260 is an Exar LDO that regulates the 5V from VBUS to 3.3V that is used as the supply voltage of
the SP336 and for the VIO_REF of the XR21B1411.
•
The SP337 is Exar’s programmable serial transceiver that can be programmed for RS-232 or RS-485/422
mode.
F
IGURE
1. E
VALUATION
B
OARD
B
LOCK
D
IAGRAM
XR21B1411
VBUS
D+
D-
GND
USB
Conn
USBD+
USBD-
VCC
Inrush
Current
Limiter
Logic
SP6260
LOWPOWER
3.3V
5V
VIO_REF
SP337
VCC
J2
J7
CON2
U3
U4
TX_EN
RX_EN#
RS232#/RS485
TX
RX
GPIO5/RTS#
GPIO4/CTS#
GPIO3/DTR#
GPIO2/DSR#
GPIO1/CD#
GPIO0/RI#
J10
J10
1 2
3 4
5 6
GND
3.3V
3.3V
