UM232R USB-Serial UART Development Module Datasheet Version 1.02

© Future Technology Devices International Ltd. 2005

Page 7

3.2 Signal Descriptions

Table 1 - Module Pin Out Description

Pin No. Name

Type Description

1

TXD

Output

Transmit Asynchronous Data Output.*

2

DTR#

Output

Data Terminal Ready Control Output / Handshake signal.*

3

RTS#

Output

Request To Send Control Output / Handshake signal.*

4

VIO

PWR

+1.8V to +5.25V supply to the UART Interface and CBUS I/O pins (1...3, 5, 6, 9...14, 22, 23).

In USB bus powered designs connect to 3V3 to drive out at 3.3V levels (connect jumper J1 pins 1 and 2

together), or connect to VCC to drive out at 5V CMOS level (connect jumper J1 pins 2 and 3 together). 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.

5

RXD

Input

Receive Asynchronous Data Input.*

6

RI#

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.*

7, 24

GND

PWR

Module ground supply pins

8

DSR#

Input

Data Set Ready Control Input / Handshake signal.*

9

DCD#

Input

Data Carrier Detect Control input.*

10

CTS#

Input

Clear to Send Control input / Handshake signal.*

11

CB4

I/O

Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default

pin function is SLEEP#. See CBUS Signal Options, Table 4.*

12

CB2

I/O

Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default

pin function is TXDEN. See CBUS Signal Options, Table 4.*

13

SLD

GND

USB Cable shield.

14

USB

Output

5V Power output USB port. For a low power USB bus powered design, up to 100mA can be sourced from the

5V supply on the USB bus. A maximum of 500mA can be sourced from the USB bus in a high power USB bus

powered design.

15, 21

VCC

PWR

or

Output

These two pins are internally connected on the module pcb. To power the module from the 5V supply on USB

bus connect jumper J2 pins 1 and 2 together (this is the module default configuration). In this case these pins

would have the same description as pin 14.

To use the UM232R module in a self powered configuration ensure that jumper J2 pins 1 and 2 are not con-

nected together, and apply an external 3.3V to 5.25V supply to one of these pins.

16

PU2

Control Pull up resistor pin connection 2. Conect to pin 17 (RST#) in a self powered configuration.

17

PU1

Control Pull up resistor pin connection 1. Connect to pin 14 (USB) in a self powered configuration

19

3V3

Output

3.3V output from integrated L.D.O. regulator. This pin is decoupled to ground on the module pcb with a 10nF

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 FT232RL’s VCCIO pin by connecting this pin to pin 4 (VIO),

or by connecting together pins 1 and 2 on jumper J1.

20

RST#

Input

Can be used by an external device to reset the FT232R. If not required can be left unconnected, or pulled up

to VCCIO.

18

CB3

I/O

Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default

pin function is PWREN#. See CBUS Signal Options, Table 4.*

22

CB1

I/O

Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default

pin function is RXLED#. See CBUS Signal Options, Table 4.*

23

CB0

I/O

Configurable CBUS I/O Pin. Function of this pin is configured in the device internal EEPROM. Factory Default

* 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.