UM232R FTDI, UM232R Datasheet - Page 18
![Interface Modules & Development Tools USB to Serial UART Dev Mod for FT232R](/photos/15/89/158917/um232r_sml.jpg)
UM232R
Manufacturer Part Number
UM232R
Description
Interface Modules & Development Tools USB to Serial UART Dev Mod for FT232R
Manufacturer
FTDI
Type
Development Moduler
Specifications of UM232R
Interface Type
USB, Serial, UART
Data Bus Width
Serial
Operating Supply Voltage
1.8 V to 5.25 V
Product
Interface Modules
Supported Devices
FT232R
Svhc
No SVHC (18-Jun-2010)
Development Tool Type
Development Kit
Kit Features
Single Chip USB To Asynchronous Serial Data Transfer Interface, Auto Transmit Buffer
Rohs Compliant
Yes
Supported Families
FT232RL
Features
Single Chip USB To Asynchronous Serial Data Transfer Interface, Auto Transmit Buffer Control
Tool / Board Applications
USB To
For Use With/related Products
FT232R
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
7.2 Self Powered Configuration
Figure 7.2 Self-Powered Configuration
Figure 7.2 illustrates the UM232R in a typical USB self powered configuration. In this case the link on
jumper J2 is removed, and an external supply is connected to the module VCC pins. Figure 7.2 illustrates a
self powered design which has a 3.5V – 5V supply.
A USB Self Powered device gets its power from its own power supply and does not draw current from the
USB bus. The basic rules for USB Self powered devices are as follows:
In order to meet requirement (i) the USB Power is used to control the RESET# Pin of the FT232R device.
When the USB Host or Hub is powered up the internal 1.5kΩ resistor on USBDP is pulled up to 3.3V, thus
identifying the devices as a full speed device to USB. When the USB Host or Hub Power is off, RESET# will
go low and the device will be held in reset. As RESET# is low, the internal 1.5kΩ resistor will not be pulled
up to 3.3V, so no current will be forced down USBDP via the 1.5kΩ pull-up resistor when the host or hub is
powered down.
To do this pin 14 (USB) is connected to PU2 and PU1 is connected to RST#. Failure to do this may cause
some USB host or hub controllers to power up erratically.
Note: When the FT232Ris in reset, the UART interface pins all go tri-state. These pins have internal 200kΩ
pull-up resistors to VCCIO, so they will gently pull high unless driven by some external logic.
© Copyright 2009 Future Technology Devices International Ltd
iii) A Self Powered Device can be used with any USB Host and both Bus and Self Powered USB Hub. In
ii) A Self Powered Device can use as much current as it likes during normal operation and USB suspend
i) A Self Powered device should not force current down the USB bus when the USB Host or Hub
Controller us powered down.
as it has its own power supply.
this case the power descriptor in the internal EEPROM should be programmed to a value of zero (self
powered).
Vcc = 3.3V – 5V
MCU
TXD
RXD
RTS#
CTS#
UM232R USB - Serial UART Development Module Incorporating Clock Generator
CTS#
GND
TXD
RXD
RTS# 3
10
12
7
1
5
J1
UM232R
1
J2
©
2
FTDI 2008
2
Document Reference No.: FT_000051
3
1
15
14
13
24
21
20
17
16
Clearance No.: FTDI# 125
VCC
USB
VCC
RST#
PU1
PU2
GND
Datasheet Version 1.04
Vcc = 3.5V – 5V
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