Digilent Minicon - Manual (Page 4)

Digilent, Inc. Minicon Reference Manual
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regulated to within the safe limits for the
Minicon board itself and any connected
peripheral boards.
The components on the Minicon will work
with any regulated voltage between 2.7V
and 5.5V. This allows direct connection of
either two-cell alkaline, or three-cell
alkaline, NiCd, or NiMh, or four-cell NiCd or
NiMh battery packs.
Warning: If the shorting block on JP9 is
in the VCC position, connection of a
power source with a voltage greater
than 5.5V will damage the board.
Each 6-pin Pmod connector provides four
I/O signals, a power connection and a
ground connection. A 3-pin jumper block
associated with each connector is used to
connect the power pin to either the VU bus
or the VCC bus.
Each 6-pin header can be jumpered to
provide either regulated or unregulated
power to peripheral modules. There are
labels on the Minicon near the jumper pins.
Place the shorting block in the VCC
position for regulated power, or in the VU
position for unregulated power supply.
Connectors JA, JB, and JC each have a
separate voltage bus selection jumper
block (JP2, JP3, and JP4, respectively).
The SPI connector (J1), the RS232/TWI
connector (J2), and auxiliary power
connector (J3), all share voltage bus
selection jumper JP1. Auxiliary power
connector J3 is provided as an alternative
source for powering off-board peripherials.
Although the Minicon normally provides
power to the Pmod connectors, power can
be supplied to the Minicon from a Pmod
connector. In this case, either the VU bus
or the VCC bus will be powered from the
Pmod connector depending on how the
associated three-pin power routing header
is jumpered. However, it is very important
to ensure that only one active power
source is supplied to the board.
For information on how to set the jumper
blocks for VU and VCC, see Table 2.
Power Supply Monitor Circuit
The Minicon’s microcontroller measures
the power supply voltage on the VU power
supply bus using the provided power
supply monitor circuit. This is useful when
powering the board from batteries as it
allows the firmware running on the
microcontroller to monitor the battery
charge state.
The power supply monitor circuit is a
voltage divider connected to analog input
ADC7. The voltage divider divides the VU
bus voltage by four, allowing monitoring of
voltages within the full range of the power
supply.
Device Programming
The Minicon has one in-system
programming connector, J1. The Digilent
parallel JTAG cable or the Digilent USB
JTAG/SPI cable can be used. When
connecting the programming cables,
ensure that the VCC and GND pin labels
on the cable match the VCC and GND pins
on the Minicon.
Programming can be accomplished using
the Digilent AVRP application, available by
free download from the Digilent web site. It
is also possible to configure the AVRDUDE
programmer in the WinAVR release for in-
system programming using the Digilent
parallel JTAG cable. See the