Evaluates: MAX3421E/MAX3420E
MAX3421 Evaluation Kit-1
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Detailed Description
of Hardware
The MAX3421 EV kit-1 has three USB connectors
(Figure 1). The MAX3421E is wired to USB connectors
J1 and J2. Plug a cable into USB Type A connector J1
when using the MAX3421E as a host. Plug a cable into
USB Type B connector J2 when using the MAX3421E
as a peripheral. Do not use J1 and J2 at the same
time. Connectors J1 and J2 have their D+ and D- pins
wired together, and are intended to be connected only
one at a time. USB peripheral controller MAX3420E is
wired to USB Type B connector J5.
When the MAX3421E (U1) operates as a host, the EV
kit must supply V
BUS
power to USB Type A connector
J1. This power must in turn be supplied to the EV kit
through power connector J3, which is located in the
middle of the board. When mated with a board such as
the Keil MCB2130, a “flying lead” can be attached
between J3 and the Keil board’s 5V IN test pad.
Alternatively, a standard 5VDC lab supply can be used.
The MAX4793 (U3) controls and current-limits the V
BUS
voltage. U1 can turn V
BUS
power on and off using one
of its GP-OUT pins (GPOUT7), and can detect a
300mA overcurrent condition on GP-IN pin, (GPIN0).
Refer to the MAX4793 data sheet for more information.
Buttons and lights are connected to both the
MAX3420E and MAX3421E controllers. U1 drives a
7-segment readout and connects to four pushbuttons
(PB1–PB4). U2 drives four LEDS and connects to push-
buttons PB5–PB8.
The MAX3420E and MAX3421E connect to two sepa-
rate SPI ports (see Table 1). This allows host and
peripheral applications to run concurrently in the same
code, when implemented on a dual-SPI microcontroller
(such as the ARM LPC2318 used on the Keil MCB2130
board). This provides an ideal USB training and debug-
ging system. The host can dispatch USB requests to
the peripheral, the peripheral can respond, and the
host can evaluate the results—all in the same C code.
Stand-Alone Operation
Although the MAX3421 EV kit-1 is designed to plug into
a Keil MCB2130 board, it also functions as a stand-
alone board that can be wired into any customer sys-
tem with an SPI interface. Table 1 shows the J4 pins
that correspond to the MAX3420E and MAX3421E
interfaces.
