UMFT240XE Datasheet, PDF (8/18 Pages) Future Technology Devices International Ltd. – UMFT240XE USB to 8-bit 245 FIFO Development Module

UMFT240XE
Version 1.0
Document Reference No.: FT_000653 Clearance No.: FTDI# 295
5.2 BUS Powered Configuration
GND
Alternative
connection
Current Flow
GND
VCCIO
3V3OUT
VCC
VBUS
Alternative
connection
Self-Sourced
3V3 TTL Mode
Jumper JP1 - Closed
Figure 5.1 – Bus Powered Configuration
Bus Powered
Mode
Jumper JP2 - Closed
A bus powered configuration draws its power from the USB host/hub. The UMFT240XE is configured by
default to be in bus powered mode.
Figure 5.1illustrates the UMFT240XE module in a typical USB bus powered design configuration. By
default 3V3OUT is connected to VCCIO, and VBUS is connected to VCC.
For a bus power configuration power is supplied from the USB VBUS:
+5V VBUS power is sourced from the USB bus and is connected to the FT240X power input (VCC)
+3.3V power is sourced from the FT240X‟s voltage regulator output and is connected to the FT240X IO
port‟s power input (VCCIO).
Interfacing the UMFT240XE module to a microcontroller (MCU), or other logic devices for bus powered
configuration is done in exactly the same way as a self powered configuration (see Section 3). Except
that it is possible for the MCU or external device to take its power supply from the USB bus (either the 5V
from the USB pin, or 3.3V from the 3V3OUT pin).
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