USB232 Converter User Guide
1-7
1.7.3 USB UART
The XR21V1410 (V1410) is an enhanced Universal Asynchronous Receiver and Transmitter (UART) with
a USB interface. 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 V1410 operates from an internal 48MHz clock therefore no external crystal/oscillator is required. With
the fractional baud rate generator, any baud rate can accurately be generated using the internal 48MHz
clock.
The large 128-byte FIFO and 384-byte RX FIFO of the V1410 helps to optimize the overall data throughput
for various applications.
Software drivers for Windows 2000, XP, and Vista are supported for the XR21V1410. See the EXAR
website for additional drivers.
Figure 5-USB UART
1.7.4 Sleep Mode
The XR21V will use the LPWR Low Power signal to shut down the RS232 transceiver and some internal
circuits. This will save power when no data signals are active. The low power mode takes effect in about 30
seconds of idle time. See Figure 5-USB UART.
