Datasheet
CP2104
16 Rev. 1.2
8. One-Time Programmable ROM
The CP2104 includes an internal one-time programmable ROM that may be used to customize the USB Vendor ID
(VID), Product ID (PID), Product Description String, Power Descriptor, Device Release Number, Device Serial
Number, GPIO configuration, Suspend pins, and modes as desired for OEM applications. If the programmable
ROM has not been customized, the default configuration data shown in Table 12 and Table 13 is used.
While customization of the USB configuration data is optional, customizing the VID/PID combination is
recommended. 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 Labs can provide a free PID for the OEM product that can
be used with the Silicon Labs VID. Customizing the serial number is also recommended if the OEM application is
one in which it is possible for multiple CP210x-based devices to be connected to the same PC.
The configuration data ROM can be programmed by Silicon Labs prior to shipment with the desired configuration
information. It can also be programmed in-system over the USB interface by adding a capacitor to the PCB. If
configuration ROM is to be programmed in-system, a 4.7 µF capacitor must be added between the VPP pin and
ground. No other circuitry should be connected to VPP during a programming operation, and V
DD
must remain at
3.3 V or higher to successfully write to the configuration ROM.
Table 12. Default USB Configuration Data
Name Value
Vendor ID 10C4h
Product ID EA60h
Power Descriptor (Attributes) 80h (Bus-powered)
Power Descriptor (Max. Power) 32h (100 mA)
Release Number 0100h (Release Version 01.00)
Serial Number Unique 8 character ASCII string (63 characters maximum)
Product Description String “CP2104 USB to UART Bridge Controller” (126 characters maximum)
Table 13. Default GPIO, UART, and Suspend Configuration Data
Name Value
GPIO.0 GPIO Input
GPIO.1 GPIO Input
GPIO.2 GPIO Input
GPIO.3 GPIO Input
Flush_Buffers Flush TX and RX FIFO on open
SUSPEND Push-pull
SUSPEND
Push-pull
RS-485 Level Active-High