PL-2303 USB Bridge Controller

Features 

Full compliance with the USB Specification v1.1 and USB CDC v1.1 

Support the RS232 Serial interface 

Support automatic handshake mode 

Support Remote wake-up and power management 

256 bytes buffer each for upstream and downstream data flow 

Support default ROM or external EEPROM for device configuration 

On chip USB transceiver 

On chip crystal oscillator running at 12M Hz 

Supports Windows 98/SE, ME, 2000, XP, Windows CE3.0, CE .NET, Linux, and Mac OS 

28 Pins SOIC package 

Overview 

The PL-2303 operates as a bridge between one USB port and one standard RS232 Serial port. The two 

large on-chip buffers accommodate data flow from two different buses. The USB bulk-type data is adopted 

for maximum data transfer. Automatic handshake is supported at the Serial port. With these, a much higher 

baud rate can be achieved compared to the legacy UART controller. 

This device is also compliant with USB power management and remote wakeup scheme. Only minimum 

power is consumed from the host during Suspend. By integrating all the function in a SOIC-28 package, this 

chip is suitable for cable embedding. Users just simply hook the cable into PC or hub’s USB port, and then 

they can connect to any RS-232 devices. 

Supported Data Formats and Programmable Baud Rate Generator 

The PL2303 USB-to-RS232 bridge controller supports versatile data formats and has a programmable baud 

rate generator. The supported data formats are shown on Table 2. The programmable baud rate generator 

supports baud rates up to 1.2M bps as shown in Table 3. 

External EEPROM and Device Configuration 

PL-2303 allows storing the configuration data in an external EEPROM. After reset, the first two bytes of 

EEPROM are checked. If the value is 067Bh, the EEPROM is valid and the contents of the EEPROM are 

loaded as the chip’s default parameters. Otherwise, the chip’s default setting is used. The content of 

EEPROM is shown in Table 4 below. 

The Device Configuration Register is used to control some vendor-specific functions. The meaning of each 

bit in Device Configuration Register is shown in Table 5. Reserved and unused pins always set to the default 

value.