Digilent 410-145P - Manual (Page 3)

Digilent, Inc. Cerebot Nano Reference Manual
www.digilentinc.com page 3 of 6
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
6-Pin Pmod Headers
The Cerebot Nano 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 virtually
any off-board I/O device.
See Table 1 for more information on
connecting peripheral modules and other
devices to the Cerebot Nano. Table 1 shows
the connectors with their designed base
function and a map to the ATmega168 I/O
ports. All I/O port signal pins can be used for
general-purpose digital I/Os.
Power Supply
The Cerebot Nano is rated for external power
ranging from 2.7 to 5.5 volts DC. The Cerebot
Nano does not feature a voltage regulator, so
care should be exercised when selecting a
power source. Using voltage outside this
range could damage the Cerebot Nano and
connected devices.
The Cerebot Nano can be powered through
any of the board’s 6-pin Pmod headers or the
J3 connector.
Each of these connectors provides a VCC and
a ground pin. A power supply providing
between 2.7 and 5.5 volts can be connected to
the VCC pin on any one of these connectors.
When the Cerebot Nano is plugged into
another Digilent microcontroller or FPGA
board, that board can power the Cerebot Nano
through the Pmod connector. The host board
should be jumpered to provide 3.3V on the
VCC pin of the Pmod connector being used.
The Cerebot Nano will then be powered by the
host board’s power supply, and will in turn
provide power from the host board to any
peripheral boards connected to the Cerebot
Nano’s other Pmod connectors.
For standalone applications, the Digilent
PmodREG1 voltage regulator module can be
used to supply 3.3 volts to the board.
Device Programming
The Cerebot Nano has one in-system-
programming (ISP) connector, J1. A Digilent
programming cable is connected to J1. Either
a parallel JTAG or USB JTAG/SPI cable can
be used. When connecting the programming
cable, ensure that the VCC and GND pin
labels from the cable match to the VCC and
GND pins on the Cerebot Nano.
A power supply must be provided to the
Cerebot Nano when programming. The
Digilent programming cable does not supply
power to the board; the board that it is plugged
into powers the programming cable. The
Digilent PmodREG1 voltage regulator module
can be used, or any appropriately regulated
power supply can be connected to J3. If the
Cerebot Nano is being used in conjunction with
another Digilent board, such as the Cerebot II
or Minicon, these boards have connectors that
can be used to supply power to the J3
connector on the Cerebot Nano using a two-
wire cable.
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 documentation for these
applications for more information on board
programming.
Connector J1 is used both for in-system-
programming and for user access to the SPI
controller. The jumper block JP1 is used to
select between the two functions. The shorting
block is placed in the RST position for in-
system-programming, and in the SS position
for user access to the SPI port.