™
Future Technology Devices International Ltd.
UC232R “ChiPi”
Minimum Component
FT232RL USB to RS232
Converter Cable
Incorporating Clock Generator Output
and FTDIChip-ID™ Security Dongle
The
UC232R
“ChiPi” is a USB to RS232 converter cable incorporating FTDI’s FT232RL USB - Serial UART interface
IC device, the latest device to be added to FTDI’s range of USB UART interface Integrated Circuit Devices. It has
been designed to use the minimum number of
The FT232RL is a USB to serial UART interface with optional clock generator output, and the new FTDIChip-ID™
security dongle feature. In addition, asynchronous and synchronous bit bang interface modes are available. USB to
serial interface designs using the FT232RL have been further simplified by fully integrating the external EEPROM,
clock circuit and USB resistors onto the device.
The FT232RL adds two new functions compared with its predecessors, effectively making it a “3-in-1” chip for some
application areas. The internally generated clock (6MHz, 12MHz, 24MHz, and 48MHz) can be brought out of the
device and used to drive a microcontroller or external logic. A unique number (the FTDIChip-ID™) is burnt into the
device during manufacture and is readable over USB, thus forming the basis of a security dongle which can be used
to protect customer application software from being copied.
The UC232R is supplied on a 16.2 mm x 41.3mm
(0.6” x 1.6”)
PCB, including the DB9 connector. A 295mm (11.8”)
USB cable with USB ‘A’ plug is fitted. All components used, including the FT232RL and RS232 level converter IC are
Pb-free (RoHS compliant).
Copyright © Future Technology Devices International Ltd. 2005
1. Features
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UC232R Converter Cable provides USB to RS232
(DB9) interface.
FCC and CE Class B Approval
Full design files available from
FTDI website.
FT232RL provides single chip USB to
asynchronous serial data transfer interface.
Entire USB protocol handled on the FT232RL chip
- No USB-specific firmware programming required.
UART interface support for 7 or 8 data bits, 1 or 2
stop bits and odd / even / mark / space / no parity.
Fully assisted hardware or X-On / X-Off software
handshaking.
Data transfer rates from 300 baud to 250 kilobaud
at RS232 levels.
FTDI’s royalty-free VCP and D2XX drivers
eliminate the requirement for USB driver
development in most cases.
In-built support for event characters and line break
condition.
New USB FTDIChip-ID™ feature.
FIFO receive and transmit buffers for high data
throughput.
Adjustable receive buffer timeout.
Integrated 1024 bit internal EEPROM for storing
USB VID, PID, serial number and product
description strings.
Page 2
1.1 Hardware Features
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Device supplied preprogrammed with unique USB
serial number.
Support for USB suspend and resume.
Converter cable supply voltage comes from VCC
- no external supply required.
FT232RL has integrated USB resistors.
Integrated power-on-reset circuit in FT232RL IC
device.
Fully integrated clock in FT232RL - no external
crystal, oscillator, or resonator required.
FT232RL has fully integrated AVCC supply filtering
- No separate AVCC pin and no external R-C filter
required.
USB bulk transfer mode.
Low operating and USB suspend current.
Low USB bandwidth consumption.
UHCI / OHCI / EHCI host controller compatible
USB 2.0 Full Speed compatible.
-40°C to 85°C extended operating temperature
range.
Supplied on 16.2 mm x 41.3mm (0.6” x 1.6”)
61.0mm x 32.0mm (2.40” x 1.26”) PCB, including
DB9 RS232 connector.
Connect to a PC via standard USB ‘A’ plug on
30cm USB cable.
Royalty-Free VIRTUAL COM PORT
Royalty-Free D2XX
Direct
Drivers
(VCP) DRIVERS for...
(USB Drivers + DLL S/W Interface)
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Windows 98, 98SE, ME, 2000, Server 2003, XP.
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Windows 98, 98SE, ME, 2000, Server 2003, XP.
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Windows Vista / Longhorn*
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Windows Vista / Longhorn*
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Windows XP 64-bit.*
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Windows XP 64-bit.*
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Windows XP Embedded.
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Windows XP Embedded.
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Windows CE.NET 4.2 & 5.0
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Windows CE.NET 4.2 & 5.0
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MAC OS 8 / 9, OS-X
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Linux 2.4 and greater
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Linux 2.4 and greater
The drivers listed above are all available to download for free from the
FTDI website.
Various 3rd Party Drivers are
also available for various other operating systems - see the
FTDI website
for details.
* Currently Under Development. Contact FTDI for availability.
1.2 Driver Support
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UC232R “ChiPi” Minimum Component FT232RL USB to RS232 Converter Cable
Datasheet Version 0.90
USB to RS232 Converter
Upgrading Legacy Peripherals to USB
USB Audio and Low Bandwidth Video data transfer
PDA to USB data transfer
USB Smart Card Readers
USB Instrumentation
USB Industrial Control
USB MP3 Player Interface
1.3 Typical Applications
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USB FLASH Card Reader / Writers
Set Top Box PC - USB interface
USB Digital Camera Interface
USB Hardware Modems
USB Wireless Modems
USB Bar Code Readers
USB Software / Hardware Encryption Dongles
© Future Technology Devices International Ltd. 2005
2. Features and Enhancements of FT232R
2.1 FT232R Key Features
Page 3
This section summarises the key features and enhancements of the FT232R IC device which is used on the UC232R
“ChiPi” USB to RS232 converter cable. For further details, consult the FT232R datasheet, which is available from the
FTDI website.
Integrated Clock Circuit -
Previous generations of FTDI’s USB UART devices required an external crystal or ceramic
resonator. The clock circuit has now been integrated onto the device meaning that no crystal or ceramic resonator is
required. However, if required, an external 12MHz crystal can be used as the clock source.
Integrated EEPROM -
Previous generations of FTDI’s USB UART devices required an external EEPROM if the
device were to use USB Vendor ID (VID), Product ID (PID), serial number and product description strings other than
the default values in the device itself. This external EEPROM has now been integrated onto the FT232R chip meaning
that all designs have the option to change the product description strings. A user area of the internal EEPROM is
available for storing additional data. The internal EEPROM is programmable in circuit, over USB without any additional
voltage requirement.
Preprogrammed EEPROM -
The FT232R is supplied with its internal EEPROM preprogrammed with a serial number
which is unique to each individual device. This, in most cases, will remove the need to program the device EEPROM.
Integrated USB Resistors -
Previous generations of FTDI’s USB UART devices required two external series resistors
on the USBDP and USBDM lines, and a 1.5 kΩ pull up resistor on USBDP. These three resistors have now been
integrated onto the device.
Integrated AVCC Filtering -
Previous generations of FTDI’s USB UART devices had a separate AVCC pin - the
supply to the internal PLL. This pin required an external R-C filter. The separate AVCC pin is now connected internally
to VCC, and the filter has now been integrated onto the chip.
Less External Components -
Integration of the crystal, EEPROM, USB resistors, and AVCC filter will substantially
reduce the bill of materials cost for USB interface designs using the FT232R compared to its FT232BM predecessor.
Configurable CBUS I/O Pin Options -
There are now 5 configurable Control Bus (CBUS) lines. Options are
TXDEN
- transmit enable for RS485 designs,
PWREN#
- Power control for high power, bus powered designs,
TXLED#
- for
pulsing an LED upon transmission of data,
RXLED#
- for pulsing an LED upon receiving data,
TX&RXLED#
- which
will pulse an LED upon transmission OR reception of data,
SLEEP#
- indicates that the device going into USB
suspend mode,
CLK48 / CLK24 / CLK12 / CLK6
- 48MHz, 24MHz,12MHz, and 6MHz clock output signal options.
There is also the option to bring out bit bang mode read and write strobes (see below). The CBUS lines can be
configured with any one of these output options by setting bits in the internal EEPROM. The device is supplied with
the most commonly used pin definitions preprogrammed - see Section 8 for details.
Enhanced Asynchronous Bit Bang Mode with RD# and WR# Strobes -
The FT232R supports FTDI’s BM chip
bit bang mode. In bit bang mode, the eight UART lines can be switched from the regular interface mode to an 8-bit
general purpose I/O port. Data packets can be sent to the device and they will be sequentially sent to the interface
at a rate controlled by an internal timer (equivalent to the baud rate prescaler). With the FT232R device this mode
has been enhanced so that the internal RD# and WR# strobes are now brought out of the device which can be used
to allow external logic to be clocked by accesses to the bit bang I/O bus. This option will be described more fully in a
separate application note.
Synchronous Bit Bang Mode -
Synchronous bit bang mode differs from asynchronous bit bang mode in that the
interface pins are only read when the device is written to. Thus making it easier for the controlling program to measure
the response to an output stimulus as the data returned is synchronous to the output data. The feature was previously
seen in FTDI’s FT2232C device. This option will be described more fully in a separate application note.
CBUS Bit Bang Mode -
This mode allows four of the CBUS pins to be individually configured as GPIO pins, similar
to Asynchronous bit bang mode. It is possible to use this mode while the UART interface is being used, thus providing
up to four general purpose I/O pins which are available during normal operation. An application note describing this
feature is available separately from the
FTDI website.
UC232R “ChiPi” Minimum Component FT232RL USB to RS232 Converter Cable
Datasheet Version 0.90
© Future Technology Devices International Ltd. 2005
Page 4
Lower Supply Voltage -
Previous generations of the chip required 5V supply on the VCC pin. The FT232R will work
with a Vcc supply in the range 3.3V - 5.25V. Bus powered designs would still take their supply from the 5V on the USB
bus, but for self powered designs where only 3.3V is available and there is no 5V supply there is no longer any need
for an additional external regulator.
Integrated Level Converter on UART Interface and Control Signals
- VCCIO pin supply can be from 1.8V to 5V.
Connecting the VCCIO pin to 1.8V, 2.8V, or 3.3V allows the device to directly interface to 1.8V, 2.8V or 3.3V and other
logic families without the need for external level converter I.C. devices.
5V / 3.3V / 2.8V / 1.8V Logic Interface -
The FT232R provides
true
CMOS Drive Outputs and TTL level Inputs.
Integrated Power-On-Reset (POR) Circuit-
The device incorporates an internal POR function. A RESET# pin is
available in order to allow external logic to reset the FT232R where required. However, for many applications the
RESET# pin can be left unconnected, or pulled up to VCCIO.
Lower Operating and Suspend Current -
The device operating supply current has been further reduced to 15mA,
and the suspend current has been reduced to around 70μA. This allows greater margin for peripheral designs to meet
the USB suspend current limit of 500μA.
Low USB Bandwidth Consumption -
The operation of the USB interface to the FT232R has been designed to use
as little as possible of the total USB bandwidth available from the USB host controller.
High Output Drive Option -
The UART interface and CBUS I/O pins can be made to drive out at three times the
standard signal drive level thus allowing multiple devices to be driven, or devices that require a greater signal drive
strength to be interfaced to the FT232R. This option is enabled in the internal EEPROM.
Power Management Control for USB Bus Powered, High Current Designs-
The PWREN# signal can be used to
directly drive a transistor or P-Channel MOSFET in applications where power switching of external circuitry is required.
An option in the internal EEPROM makes the device gently pull down on its UART interface lines when the power
is shut off (PWREN# is high). In this mode any residual voltage on external circuitry is bled to GND when power is
removed, thus ensuring that external circuitry controlled by PWREN# resets reliably when power is restored.
UART Pin Signal Inversion -
The sense of each of the eight UART signals can be individually inverted by setting
options in the internal EEPROM. Thus, CTS# (active low) can be changed to CTS (active high), or TXD can be
changed to TXD#.
FTDIChip-ID™ -
Each FT232R is assigned a unique number which is burnt into the device at manufacture. This ID
number cannot be reprogrammed by product manufacturers or end-users. This allows the possibility of using FT232R
based dongles for software licensing. Further to this, a renewable license scheme can be implemented based on the
FTDIChip-ID™ number when encrypted with other information. This encrypted number can be stored in the user area
of the FT232R internal EEPROM, and can be decrypted, then compared with the protected FTDIChip-ID™ to verify
that a license is valid. Web based applications can be used to maintain product licensing this way. An application note
describing this feature is available separately from the
FTDI website.
Improved EMI Performance -
The reduced operating current and improved on-chip VCC decoupling significantly
improves the ease of PCB design requirements in order to meet FCC, CE and other EMI related specifications.
Programmable Receive Buffer Timeout -
The receive buffer timeout is used to flush remaining data from the
receive buffer. This time defaults to 16ms, but is programmable over USB in 1ms increments from 1ms to 255ms, thus
allowing the device to be optimised for protocols that require fast response times from short data packets.
Baud Rates -
The FT232R supports all standard baud rates and non-standard baud rates from 300 Baud up to 3
Megabaud. Achievable non-standard baud rates are calculated as follows -
Baud Rate = 3000000 / (n +
x)
where n can be any integer between 2 and 16,384 ( = 2
14
) and
x
can be a sub-integer of the value 0, 0.125, 0.25,
0.375, 0.5, 0.625, 0.75, or 0.875. When n = 1,
x
= 0, i.e. baud rate divisors with values between 1 and 2 are not
possible.
This gives achievable baud rates in the range 183.1 baud to 3,000,000 baud. When a non-standard baud rate is
required simply pass the required baud rate value to the driver as normal, and the FTDI driver will calculate the
required divisor, and set the baud rate. See FTDI application note AN232B-05 for more details.
UC232R “ChiPi” Minimum Component FT232RL USB to RS232 Converter Cable
Datasheet Version 0.90
© Future Technology Devices International Ltd. 2005
Page 5
Extended Operating Temperature Range
- The FT232R operates over an extended temperature range of -40º to
+85º C thus allowing the device to be used in automotive and industrial applications.
New Package Options
- The FT232R is available in two packages - a compact 28 pin SSOP ( FT232RL) and an
ultra-compact 5mm x 5mm pinless QFN-32 package ( FT232RQ). Both packages are lead ( Pb ) free, and use a
‘green’ compound. Both packages are fully compliant with European Union directive 2002/95/EC. The MM232R
module uses a FT232RQ device in its design.
Figure 1 - The UC232R “ChiPi” USB to RS232 Converter Cable.
UC232R “ChiPi” Minimum Component FT232RL USB to RS232 Converter Cable
Datasheet Version 0.90
© Future Technology Devices International Ltd. 2005
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