UMFT221XE Datasheet, PDF (8/18 Pages) Future Technology Devices International Ltd. – UMFT221XE USB to 8-bit SPI/FT1248 Development Module

UMFT221XE
Version 1.0
Document Reference No.: FT_000651 Clearance No.: FTDI# 293
5.2 Bus Powered Configuration
Alternative
connection
Current Flow
GND
VCCIO
3V3OUT
GND
VCC
VBUS
Alternative
connection
Self-Sourced
3V3 TTL Mode
Jumper JP1 - Closed
Bus Powered
Mode
Jumper JP2 - Closed
Figure 5.1 – Bus Powered Configuration
A bus powered configuration draws its power from the USB host/hub. The UMFT221XE is configured by
default to be in bus powered mode.
Figure 5.1 illustrates the UMFT221XE 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 FT221X power input (VCC)
+3.3V power is sourced from the FT221X‟s voltage regulator output and is connected to the FT221X IO
port‟s power input (VCCIO).
Interfacing the UMFT221XE 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 5.3), 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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