Reference Design HFRD-34.0 (Rev.3, 05/08) Maxim Integrated Products
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MAX3420
The MAX3420E contains the digital logic and analog circuitry necessary to implement a full-
speed USB peripheral compliant to USB specification rev 2.0. A built-in full-speed transceiver
features ±15kV ESD protection and programmable USB connect and disconnect. An internal
serial-interface engine (SIE) handles low-level USB protocol details such as error checking
and bus retries. The MAX3420E operates using a register set accessed by an SPI™
interface that operates up to 26MHz. Any SPI master (microprocessor, ASIC, DSP, etc.) can
add USB functionality by using the simple 3- or 4-wire SPI interface.
Additional information:
www.maxim-ic.com/MAX3420
MAX4788
The MAX4785–MAX4788 family of switches feature internal current limiting to prevent host
devices from being damaged due to faulty load conditions. These analog switches have a low
0.7Ω on-resistance and operate from a 2.3V to 5.5V input voltage range. They are available
with guaranteed 50mA and 100mA current limits, making them ideal for load-switching
applications.
Additional information:
www.maxim-ic.com/MAX4788
7 Navigation Menu
HFRD-34.0 is controlled through an easy-to-use
navigation switch (up, down, left, right, and push
to select) and LCD display. Through this menu-
based interface, the user can set, save, and load
configurations and control a variety of other
features available in the reference design. The
table below details the menu options available.
Table 1. Navigation Menu Details
Menu* Index LCD Label Action Taken by Pushing “Select” on Menu Item
MM 1 Configuration
Configuration Menu (CM) is opened
MM 2 Video Switch
Video Switch Menu (VSM) is opened
MM 3 Audio Switch
Audio Switch Menu (ASM) is opened
MM 4 USB Switch
USB Switch Menu (USM) is opened
MM 5 Audio Control
Audio Control Menu (ACM) is opened
MM 6 Advanced Ctrl
Advanced Control Menu (ADVM) is opened
CM 1 Load Config
Opens a menu to allow the user to load one of four saved
configurations.
CM 2 Save Config
Opens menu to allow the user to save the current configuration to
one of four memory locations. Saved configurations are retained
during power cycles.
