
Copyright © 2010 Future Technology Devices International Limited 12
Document Reference No.: FT_000077
USB TO RS232 SERIAL CONVERTER RANGE OF CABLES Datasheet Version 1.3
Clearance No.: FTDI# 51
Appendix A - Cable EEPROM Configuration
Each USB-RS232 cable is controlled by the FTDI FT232R IC. This FT232R device contains an EEPROM
which contains the USB configuration descriptors for that device. When the cable is plugged into a PC or a
USB reset is performed, the PC will read these descriptors. The default values stored into the internal
EEPROM are defined in Table 0.1
A unique serial number is generated and programmed into
the EEPROM during device final test.
Pull down I/O Pins in USB
Suspend
Enabling this option will make the device pull down on the
UART interface lines when the power is shut off (PWREN#
is high).
Returns USB 2.0 device description to the host.
Note: The device is a USB 2.0 Full Speed device (12Mb/s)
as opposed to a USB 2.0 High Speed device (480Mb/s).
Enables the high drive level on the UART and CBUS I/O
pins.
Makes the device load the VCP driver interface for the
device.
Signal on this pin becomes TXD# if enable.
Signal on this pin becomes RXD# if enable.
Signal on this pin becomes RTS if enable.
Signal on this pin becomes CTS if enable.
Table 0.1 Default Internal EEPROM Configuration
The internal EEPROM in the cable can be re-programmed over USB using the utility program MPROG.
MPROG can be downloaded from the www.ftdichip.com. Version 2.8a or later is required for the FT232R
chip. Users who do not have their own USB Vendor ID but who would like to use a unique Product ID in
their design can apply to FTDI for a free block of unique PIDs. Contact FTDI support for this service.
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