Digilent 210-161P User Manual

FFXX22 MMIIBB™
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Revision: January 14, 2009
Note: This document applies to REV A of the board.

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Overview

The Digilent FX2 Module Interface Board (MIB)
offers a ready-made solution for interfacing
peripheral modules to Digilent system boards.

Features include:

• FX2 peripheral board connector

• four 12-pin and two 6-pin Pmod

connectors

• access to JTAG scan chain

• access to signals for test points

• provision for oscillator for clock input to

system board

Functional Description

Power Connections

The FX2 MIB provides two power busses and
a ground bus. The two power busses are
labeled VCC and VCCFX2. These two busses
are made available at each connector position
on the board. There is also a ground plane that
connects the ground pins from all connectors.

The usual Digilent convention is to power the
VCC bus at 3.3V and the VCCFX2 bus at 5.0V.
However, depending on the system board
connected and the power supply used, other
voltages may be present. Use caution when
using any voltage other than 3.3V on the VCC
bus. Most Digilent system boards will be
damaged if the voltage on the VCC bus is
greater than 3.3V.

FX2 connector J10 is provided on one side of
the board for connection to Digilent system
boards, like the Nexys2, that contain an FX2­style connector. The Digilent FX2 connector
signal convention provides for forty general­purpose I/O signals, three clock signals, JTAG
signals, and power busses.

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FX2 MIB Block Diagram

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FX2 MIB Reference Manual

The forty general-purpose I/O signals from the
FX2 connector are brought out to connector
J7. These signals are labeled IO1-IO40. See
Table 1 for a description of the relationship
between FX2 connector pins and signal names
on J7. The remaining signals from the FX2
connector are brought out to connectors J8,
J9, J11, and J12. See Table 1 for a description
of the relationship between FX2 connector pins
and connectors J8 and J9 signal names.
In addition to the FX2 connector signals,
connector J11 and J12 also provide access to
the power and ground busses.

Pmod Connectors

Digilent Pmods provide various peripheral
functions. These can be as simple as buttons
or switches for inputs and LEDs for outputs, or
as complex as graphical LCD display panels,
accelerometers, and keypads.

All Digilent Pmods use either a six-wire
interface or a twelve-wire interface. The six­wire interface provides four I/O signals, power,
and ground. The twelve-wire interface provides
eight I/O signals, two powers, and two
grounds. The signal definitions for the I/O
signals as well as the voltage requirements for
the power supply depend on the specific
module.

The FX2 MIB provides four twelve-pin and two
six-pin Pmod connectors.

The twelve-pin connector provides access
such that the top set of four pins are the odd
labeled signals while the bottom set are even
labeled signals. See Table 2.

The signals for Pmod connectors J1-J6 are
brought out to connector J7. These signals are
labeled IO1-IO40.

Each Pmod connector has an associated
power select jumper. The power select jumper
for J1 is JP1, and so on. These jumpers are
used to select one of the two power busses on
the FX2 MIB to provide power to the power
supply pin on a Pmod plugged into that
connector position. Placing a shorting block in
the 3V3 position provides VCC power to the

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Pmod. Placing a shorting block in the 5V0
position provides VCCFX2 power to the Pmod.
Place a shorting block so that it hangs off of
the center pin only to disconnect power to the
Pmod.

FPGA Configuration

The FX2 MIB provides JTAG access via
unloaded jumper J9. Given that the jumper
JP7 labeled JTSEL is shorted, this jumper
allows a connected board to be programmed
via a JTAG cable.

See Table 1 for a description of the
relationship between the FX2 connector pins
and the connections on the JTAG jumper J9.

Clocks

The FX2 MIB provides an oscillator clock input
to a system board via socket connector IC1.
This socket can be used to input a clock signal
to a system board when an external oscillator
is placed on it. It will then output a clock signal
on the CLKIO pin of the FX2 connector.

The unloaded jumper J8 provides access to all
possible clock signals into and out of the FX2
MIB. This includes the signal CLKIO from the
external oscillator socket connector as well as
CLKIO and CLKOUT signals directly from the
FX2 connector.

See Table1 for more details.

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