Digilent Minicon - Manual (Page 3)

Digilent, Inc. Minicon Reference Manual
www.digilentinc.com
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6-pin Pmod Headers
The Minicon has five 6-pin header
connectors for connecting to general-
purpose, off-board digital I/O, or to specific
ATmega168 features like analog-to-digital
converters or pulse width modulators. Each
6-pin connector provides four signals,
power, and ground. These connectors are
specifically designed to work with the
Digilent Pmod line of peripheral boards, but
can be used to connect to any off-board
I/O devices.
See Table 1 for more information on
connecting peripheral modules and other
devices to the Minicon.
Table 1 shows the
connectors with their designed base
function and a map to the ATmega168 I/O
ports. All I/O port pins can be used for
general-purpose digital I/Os.
Power Supply Connectors
The Minicon is rated for external power
ranging from 3.6 to 9 volts DC. Using
voltage outside this range could damage
the Minicon and connected devices.
The Minicon can be powered from a power
supply connected to one of three external
power connectors, or it can be powered
through any of the board’s 6-pin Pmod
headers. The three external power supply
connectors are J6, J7, and J8.
Connector J6 is a 5.5mm x 2.1mm coaxial
barrel connector. The AC power adapter,
available from Digilent, is attached to this
connector. This is useful for desktop
development and testing where use of
batteries is cost prohibitive. This connector
is wired so that the center pin provides the
positive voltage and the outer shell is
grounded.
Connector J7 is a two-pin screw terminal.
This connector can be used with laboratory
bench supplies, or for attachment to
battery packs.
Connector J8 is a two-pin male header that
provides an alternate connection to battery
packs or other power sources. Digilent has
available either two or three cell battery
packs that can be attached directly to this
connector.
Power supply connectors J6, J7, and J8
are connected in parallel. A power source
should be connected to only one of these
three connectors at a time.
Warning: Use the proper polarity when
connecting a power source to J7 or J8.
A reversed connection will damage the
board. The proper polarity is silk-
screened on the board near each
connector.
The Minicon provides an on-board voltage
regulator that produces the 3.3V operating
voltage for the board. The VU power bus
provides the input to the voltage regulator,
and the VCC power bus is the regulated
output. Jumper JP9 is used to route
external power through the on-board
regulator or to bypass the regulator.
The power supply connectors, J6, J7, and
J8 are connected in parallel to the center
pin, VE, on JP9. If the shorting block is
placed in the VU position, the supplied
voltage is routed through the voltage
regulator and regulated to 3.3V to power
the VCC bus. If the shorting block is placed
in the VCC position, the supplied voltage is
routed around the on-board regulator and
powers the VCC bus directly. In this case,
the supplied voltage must be externally