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Evaluates: USB2GPIO

USB2GPIO# Adapter Board

Detailed Description of Hardware

The USB2GPIO# board uses the FT2232HQ (U1), a USB

2.0 high-speed (480Mbps)-to-UART/FIFO IC, to process

commands sent by a program running on the PC. Each

particular EV kit has its own custom software specific

to that kit. The operation of this board is USB-to-dual-

The subsystem block diagram and simplified power tree

are shown in Figure 3.

The VCCIO and +3.3V voltage supplies are generated

by two MAX1556ETBs (U5 and U6), 1.2A, highly efficient

PWM step-down DC-DC converters. The 5V supply volt-

age input for these ICs is provided by the Micro-USB

supply terminal available from the laptop. The 3V3 sup-

ply provides power to the FDTI chip’s VREGIN pin and

its internal oscillator through an LC filter, and the 4K

engine is powered by 3.3V at the VREGIN pin and the core

voltage of 1.8V for the IC is generated at VREGOUT. This

VCORE is used within the FTDI IC itself for its internal logic

processes and there is an external 12MHz crystal across

OSCI and OSCO pins of the FTDI IC. See USB2GPIO#

Adapter Board Schematic for details.

Pmod and Connector Supply Voltages

The USB2GPIO# is designed to supply power (V_OUT) to

external boards through the connectors X2 and X3. This

voltage is defined by the type of board connected to X3,

and when the user selects that tab in the Munich GUI,

V_OUT is automatically set to the correct level, either

1.8V, 2.5V, 3.3V, or 5.0V.

Figure 3. USB2GPIO# Subsystem Block Diagram

USB

FT2232HQ

U1

SWITCHES

MAX4983, U2, U4

DC-DC

MAX1556, U5

DC-DC

MAX1556, U6

12-PIN

X3

20-PIN

X2

+5V

VCCIO

+3V3

V_OUT

SPI/I2C

V_OUT

GPIO

SELE CT

VOLTAGE

OUTPUT

M1 - M5

V_OUT

VCCIO

+5V

M3

M1

VCCIO

+3V3