CP2103

Preliminary Rev. 0.3

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6. Asynchronous Serial Data Bus (UART) Interface

The CP2103 UART interface consists of the TX (transmit) and RX (receive) data signals as well as the RTS, CTS,

DSR, DTR, DCD, and RI control signals. The UART supports RTS/CTS, DSR/DTR, and X-On/X-Off handshaking.

The UART is programmable to support a variety of data formats and baud rates. If the Virtual COM Port drivers are

used, the data format and baud rate are set during COM port configuration on the PC. If the USBXpress drivers are

used, the CP2103 is configured through the USBXpress API. The data formats and baud rates available are listed

in Table 8.

7. GPIO Pins

The CP2103 supports (4) user-configurable GPIO pins for status and control information. More information

regarding the configuration and usage of these pins can be found in “AN144: CP210x Customization Guide” and

8. Internal EEPROM

The CP2103 includes an internal EEPROM that may be used to customize the USB Vendor ID (VID), Product ID

(PID), Product Description String, Power Descriptor, Device Release Number and Device Serial Number as

desired for OEM applications. If the EEPROM is not programmed with OEM data, the default configuration data

shown in Table 9 is used.

While customization of the USB configuration data is optional, it is recommended to customize the VID/PID

combination. A unique VID/PID combination will prevent the driver from conflicting with any other USB driver. A

vendor ID can be obtained from www.usb.org or Silicon Laboratories can provide a free PID for the OEM product

that can be used with the Silicon Laboratories VID. It is also recommended to customize the serial number if the

OEM application is one in which it is possible for multiple CP2102-based devices to be connected to the same PC.

The internal EEPROM is programmed via the USB. This allows the OEM's USB configuration data and serial

number to be written to the CP2103 on-board during the manufacturing and testing process. A stand-alone utility

for programming the internal EEPROM is available from Silicon Laboratories. A library of routines provided in the

into custom software used by the OEM to streamline testing and serial number management during manufacturing.

The EEPROM has a typical endurance of 100,000 write cycles with a data retention of 100 years.

USB descriptors can be locked to prevent future modification.

Table 8. Data Formats and Baud Rates

Data Bits

5, 6, 7, and 8

Stop Bits

Parity Type None, Even, Odd, Mark, Space

51200, 56000, 57600, 64000, 76800, 115200, 128000, 153600, 230400, 250000, 256000,

Notes:

5. 5-bit only.

6. Additional baud rates are supported. See “AN205: CP210x Baud Rate Support”.

7. 7 or 8 data bits only.