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DLP Design USB-Parallel FIFO Module DLP-USB245R, User Manual, Page: 8 / 13

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DLP Design USB-Parallel FIFO Module DLP-USB245R User Manual Download Page 8

Rev. 1.0 (November 2008)                                           8                                              © DLP Design, Inc.

 

 

8.0  DEVICE CONFIGURATION EXAMPLES 

 

USB Bus-Powered and Self-Powered Configurations 

 
 

 
Figure 1. 
 
 

 
 
 
 

 

 
 
The figure above illustrates a typical USB bus-powered configuration.  A USB bus-powered 
device gets its power from the USB bus.  Basic rules for USB bus-powered devices are as 
follows: 
 
1.  On plug-in to USB, the module and external circuitry should draw no more than 100mA on 
the 5-volt line from the USB host. 
 
2.  In USB Suspend Mode, the module and external circuitry should draw no more than 2.5mA. 
 
3.  A bus-powered, high-power USB device (one that draws more than 100mA) should use one 
of the CBUS pins configured as PWREN# to keep the current below 100mA on plug-in and 
below 2.5mA on USB Suspend. 
 
4.  A design that consumes more than 100mA in total cannot be plugged into a USB  
bus-powered hub. 
 
5.  No USB target system can draw more than 500mA from the USB bus. The power descriptors 
in the internal EEPROM of the FT245R should be programmed to match the total current drawn 
by the target system. 
 
Note:  If using PWREN# (available using the CBUS), the I/O pin should be pulled to VCCIO 
using a 10k-ohm resistor. 

 
 

 

9

7
8

Bus-Powered

5V System

Summary of Contents for USB-Parallel FIFO Module DLP-USB245R

Page 1: ...eceive buffer and 128 byte transmit buffer utilizing buffer smoothing technology to allow for high data throughput FTDI s royalty free Virtual COM Port VCP and direct D2XX drivers eliminate the requirement for USB driver development in most cases Unique USB FTDIChip ID feature Configurable FIFO interface I O pins Synchronous and asynchronous bit bang interface options with RD and WR strobes Device...

Page 2: ...P Drivers for Windows 98 98SE ME 2000 Server 2003 XP and Server 2008 Windows XP and XP 64 bit Windows Vista and Vista 64 bit Windows XP Embedded Windows CE 4 2 5 0 and 6 0 Mac OS 8 9 OS X Linux 2 4 and greater Royalty Free D2XX Direct Drivers USB Drivers DLL S W Interface for Windows 98 98SE ME 2000 Server 2003 XP and Server 2008 Windows XP and XP 64 bit Windows Vista and Vista 64 bit Windows XP E...

Page 3: ...sor via I O ports To send data from the peripheral to the host computer simply write the byte wide data into the module when TXE is low If the 128 byte transmit buffer fills up or is busy storing the previously written byte the device takes TXE high in order to stop further data from being written until some of the FIFO data has been transferred over USB to the host When the host sends data to the...

Page 4: ...active to RXF 0 25 nS T6 RXF Inactive After RD Cycle 80 nS Load 30pF T TI IM ME E D DE ES SC CR RI IP PT TI IO ON N M MI IN N M MA AX X U UN NI IT T T7 WR Active Pulse Width 50 nS T8 WR to WR Pre Charge Time 50 nS T9 Valid Data Setup to WR Falling Edge 20 nS T10 Valid Data Hold Time from WR Inactive 0 nS T11 WR Inactive to TXE 5 25 nS T12 TXE Inactive After WR Cycle 80 nS Load 30pF T6 T5 RXF T1 T2...

Page 5: ...e floppy disk or folder since the INF files determine which set of drivers to load for each operating system version Once loaded the VCP drivers will allow your application software running on the host PC to communicate with the DLP USB245R as though it were connected to a COM RS 232 port In addition to VCP drivers FTDI s D2XX direct drivers for Windows offer an alternative solution to the VCP dri...

Page 6: ...th a USB port 1 Download the CDM device drivers from either www dlpdesign com or www ftdichip com Unzip the drivers into a folder on the hard drive 2 Connect the DLP USB245R board to the PC via a USB A to mini B cable This action initiates the loading of the USB drivers When prompted select the folder where the device drivers were stored in Step 1 Windows will then complete the installation of the...

Page 7: ...from a high impedance state to the current byte in the FIFO s buffer Taking RD high returns the data pins to a high impedance state and prepares the next byte if available in the FIFO to be read 12 WR When taken from a high to a low state WR reads the 8 data lines and writes the byte into the FIFO s transmit buffer Data written to the transmit buffer is sent to the host PC within the TX buffer tim...

Page 8: ...xternal circuitry should draw no more than 2 5mA 3 A bus powered high power USB device one that draws more than 100mA should use one of the CBUS pins configured as PWREN to keep the current below 100mA on plug in and below 2 5mA on USB Suspend 4 A design that consumes more than 100mA in total cannot be plugged into a USB bus powered hub 5 No USB target system can draw more than 500mA from the USB ...

Page 9: ...e can take as much current as it likes during normal operation and during USB Suspend as it has its own power supply 3 A self powered device can be used with any USB host and both bus and self powered USB hubs Figure 3 Figure 3 shows how to configure the DLP USB245R to interface with a 3 3V logic device In this example the target electronics provide the 3 3 volts via the VCCIO line Pin 7 which in ...

Page 10: ...its own reset circuitry so that it will automatically reset itself when power is reapplied on coming out of Suspend 2 Set the soft pull down option bit in the FT245R EEPROM 3 For USB high power bus powered applications ones that consume greater than 100mA and up to 500mA of current from the USB bus the power consumption of the application must be set in the Max Power Field in the internal FT245R E...

Page 11: ... supplied on an as is basis and no warranty as to their suitability for any particular purpose is either made or implied DLP Design Inc will not accept any claim for damages whatsoever arising as a result of the use or failure of this product Your statutory rights are not affected This product or any variant of it is not intended for use in any medical appliance device or system in which the failu...

Page 12: ...inary information that may be subject to change without notice 12 0 CONTACT INFORMATION DLP Design Inc 1605 Roma Lane Allen TX 75013 Phone 469 964 8027 Fax 415 901 4859 Email Sales sales dlpdesign com Email Support support dlpdesign com Website URL http www dlpdesign com ...

Page 13: ...E C4 47uF J1 245 Version 1 2 3 4 5 6 7 8 9 18 17 16 15 14 13 12 11 10 C5 1uF C2 01 CN1 USB B Conn 1 2 3 4 5 C3 1uF C1 10 10 Tant FB1 240 1018 1 1 2 C7 47pF C6 47pF U1 FT245RL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 D0 D4 D2 VCCIO D1 D7 GND VCCIN NC D5 D6 D3 PWREN RD WR USBDP USBDM 3V3OUT GND RESET VCC5 IN GND TXE RXF AVCC NC AGND TEST OSCI OSCO ...

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