4.2 SSOP-28 Package Signal Descriptions
Table 1 - SSOP Package Pin Out Description
Pin No. Name
15
16
4
USBDP
USBDM
VCCIO
Page 8
Type Description
I/O
I/O
PWR
USB Data Signal Plus, incorporating internal series resistor and 1.5kΩ pull up resistor to 3.3V
USB Data Signal Minus, incorporating internal series resistor.
+1.8V to +5.25V supply to the UART Interface and CBUS group pins (1...3, 5, 6, 9...14, 22, 23). In USB bus
powered designs connect to 3V3OUT to drive out at 3.3V levels, or connect to VCC to drive out at 5V CMOS
level. This pin can also be supplied with an external 1.8V - 2.8V supply in order to drive out at lower levels. It
should be noted that in this case this supply should originate from the same source as the supply to Vcc. This
means that in bus powered designs a regulator which is supplied by the 5V on the USB bus should be used.
Device ground supply pins
3.3V output from integrated L.D.O. regulator. This pin should be decoupled to ground using a 100nF capacitor.
The prime purpose of this pin is to provide the internal 3.3V supply to the USB transceiver cell and the internal
1.5kΩ pull up resistor on USBDP. Up to 50mA can be drawn from this pin to power external logic if required.
This pin can also be used to supply the FT232R’s VCCIO pin.
3.3V to 5.25V supply to the device core.
Device analog ground supply for internal clock multiplier
No internal connection.
Can be used by an external device to reset the FT232R. If not required can be left unconnected, or pulled up
to VCCIO.
Puts the device into I.C. test mode. Must be tied to GND for normal operation.
Input to 12MHz Oscillator Cell. Optional - Can be left unconnected for normal operation. *
Output from 12MHz Oscillator Cell. Optional - Can be left unconnected for normal operation if internal oscilla-
tor is used. *
Transmit Asynchronous Data Output.
Data Terminal Ready Control Output / Handshake signal.
Request To Send Control Output / Handshake signal.
Receive Asynchronous Data Input.
Ring Indicator Control Input. When remote wake up is enabled in the internal EEPROM taking RI# low can be
used to resume the PC USB host controller from suspend.
Data Set Ready Control Input / Handshake signal.
Data Carrier Detect Control input.
Clear to Send Control input / Handshake signal.
Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default
function is SLEEP#. See CBUS Signal Options,
Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default
function is TXDEN. See CBUS Signal Options,
Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default
function is PWREN#. See CBUS Signal Options,
Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default
function is RXLED#. See CBUS Signal Options,
Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default
function is TXLED#. See CBUS Signal Options,
USB Interface Group
Power and Ground Group
7, 18, 21
17
GND
3V3OUT
PWR
Output
20
25
8, 24
19
26
27
28
VCC
AGND
NC
RESET#
TEST
OSCI
OSCO
PWR
PWR
NC
Input
Input
Input
Output
Miscellaneous Signal Group
UART Interface and CBUS Group **
1
2
3
5
6
9
10
11
12
13
14
22
23
TXD
DTR#
RTS#
RXD
RI#
DSR#
DCD#
CTS#
CBUS4
CBUS2
CBUS3
CBUS1
CBUS0
Output
Output
Output
Input
Input
Input
Input
Input
I/O
I/O
I/O
I/O
I/O
* Contact
for details on how to use an external crystal, ceramic resonator, or oscillator with the
FT232R.
** When used in Input Mode, these pins are pulled to VCCIO via internal 200kΩ resistors. These pins can be
programmed to gently pull low during USB suspend ( PWREN# = “1” ) by setting an option in the internal EEPROM.
FT232R USB UART I.C. Datasheet Version 1.04
© Future Technology Devices International Ltd. 2005
FTDI [ FUTURE TECHNOLOGY DEVICES INTERNATIONAL LTD. ]
