MM232R Mini USB-Serial UART Development Module Datasheet Version 1.00

© Future Technology Devices International Ltd. 2005

Page 

3.2 Signal Descriptions

Table 1 - Module Pin Out Description

Pin No. Name

Type Description

1

SHEILD

GND

USB Cable shield.

2

VCC

PWR

or Input

To power the module from the 5V supply on USB bus connect pins 15 (USBPWR) and 14 (VCC50) together.

In this case this pin becomes a 5V output, and can be used to supply the VCCIO pin, or to supply external

logic.

To use the MM232R module in a self powered configuration supply an external 3V - 5V supply to this pin, and

do not connect together pins 15 and 14.

3

VCCIO

+1.8V to +5.25V supply to the FT232RQ’s UART Interface and CBUS I/O pins. In USB bus powered designs

connect to 3V3 to drive out at 3.3V levels (connect VCCIO to VCC3O), or connect to VCC to drive out at 5V

CMOS level (connect VCCIO to VCC). This pin can also be supplied with an external 1.8V - 2.8V supply in or-

der 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.

4

VCC3O

Output

3.3V output from integrated L.D.O. regulator. This pin is decoupled to ground on the module pcb with 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 FT232RQ’s VCCIO pin by connecting this pin to pin 3

(VCCIO).

5

TXD

Output

Transmit Asynchronous Data Output.*

6

RTS#

Output

Request To Send Control Output / Handshake signal.*

7

RXD

Input

Receive Asynchronous Data Input.*

8

CTS#

Input

Clear to Send Control input / Handshake signal.*

9

CLK12

Output

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

10

SLEEP#

Output

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

pin function for the MM232R module is SLEEP# - Goes low during USB suspend mode. Typically used to

power down an external TTL to RS232 level converter I.C. in USB to RS232 converter designs. This pin is the

11

RESET#

Input

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

to VCCIO.

12

PWREN#

Output

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

pin function for the MM232R module is PWREN# - Goes low after the device is configured by USB, then high

during USB suspend. Can be used to control power to external logic P-Channel logic level MOSFET switch.

Enable the interface pull-down option when using the PWREN# pin in this way. See CBUS Signal Options,

13

GND

GND

Module ground supply pins

14

VCC5O

PWR

Module 3.3V - 5.25V power supply input. To power the module from the 5V supply on USB bus connect pins

15 (USBPWR) and 14 (VCC50) together.

15

USBPWR 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. Connect to Pin 14 (VCC50) to power the MM232R module from the USB bus.

16

SHEILD

GND

USB Cable shield.

* 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.