USB-COM485-PLUS-4 FTDI, USB-COM485-PLUS-4 Datasheet - Page 16

• Manufacturer Part Number: USB-COM485-PLUS-4
• Description: MODULE, DEV, USB-RS485, 4 COM PORT
• Manufacturer: FTDI
• Type: Developmentr

Specifications of USB-COM485-PLUS-4

• Mcu Supported Families: FT232R, FT2232, FT232BM
• Kit Features: Works With USB 1.1 & 2.0 Host And Hub Ports, FIFO
• Svhc: No SVHC (18-Jun-2010)
• 2.0 Host And Hub Ports, Fifo: 2KB Transmit Buffer, 2KB Receive Buffer
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3
3.1
3.1.1 USB
The USB-COM485-PLUS4 is a downstream USB 2.0 Device. A standard USB “mini B” receptacle is
mounted inside the USB-COM485-PLUS4 to facilitate connection to an upstream USB Host or Hub.
Table 3.1 – USB " mini B" Receptacle Pin-Out
3.1.2 RS485
The RS485 ports are configured as Data Terminal Equipment (DTE), with a 9-contact D-Sub Pin
connector. Pin assignments are according to TIA/EIA-485. In addition, pin9 of DB9 provides +5VDC to
an external device with a maximum current draw of 450mA once the USB-COM485-PLUS4 has been
enumerated by the system.
Table 3.2 – DE-9P RS485 Pin-Out
Pin Number
Pin Number
Connections
Shield
External Connectors
1
2
3
4
5
1
2
3
4
5
6
7
8
9
Case Ground
Bidirectional
Bidirectional
Pin Type
PWR = +5V DC output
Ground
GND = signal ground
Power
ID
Copyright © 2010 Future Technology Devices International Limited
Input/Output
Input/Output
Pin Type
Output
Input
Input
N/A
N/A
Description
VBUS = USB Power provided from upstream USB Host or Hub
D– = USB data signal, negative polarity
D+ = USB data signal, positive polarity
No connected
GND = USB signal ground
Drain = typically connected to the host PC case
Description
COM485-PLUS4 is the first or last device in a multi-drop RS485
COM485-PLUS4 is the first or last device in a multi-drop RS485
Local echo function control output pin. Connect pin7 and pin 8
Pin 2 of 120R Terminating Resistor. Only Required if the USB-
Pin 1 of 120R Terminating Resistor. Only Required if the USB-
can disable the local echo function. The local echo is enabled
can disable the local echo function. The local echo is enabled
Local echo function control input pin. Connect pin7 and pin 8
System, to meet RS485 Termination Requirements.
System, to meet RS485 Termination Requirements.
by default.
by default.
DATA+
DATA-
GND
PWR
Document Reference No.: FT_000153
N/A
N/A
USB-COM485-PLUS4 Datasheet
Clearance No.: FTDI# 108
Version 1.2
15