Digilent chipKIT Network Shield Reference Manual And User's Guige

cchhiippKKIIT

T

™

™

NNeettwwoorrkk SShhiieelldd

BBooaarrdd RReeffeerreennccee MMaannuuaal

l

Revision: June 27, 2012

1300 NE Henley Court, Suite 3

Pullman, WA 99163

[phone] Voice | [phone] Fax

Overview

The chipKIT Network Shield is an input/output
expansion board designed for use with the
chipKIT Max32™. It provides the additional
circuitry and connectors to allow the advanced
communications features of the
PIC32MX795F512L on the Max32 to be
utilized.

The Network Shield provides a 10/100 Mbps
Ethernet PHY to allow connection to an
Ethernet network. It provides the connectors
and load switch to support use of the USB 2.0
OTG controller to implement USB device, USB
host or OTG operation. It also provides two
CAN transceivers and connectors to allow
connection to two independent CAN networks.
Connectors are provided to allow connection to
two of the I2C busses supported by the Max32.

In addition to the communications features, the
Network Shield also adds a 256Kbit I2C
EEPROM for non-volatile data storage and a

32.768Khz oscillator to allow use of the Real
Time Clock/Calendar (RTCC) peripheral in the
PIC32 microcontroller.

The Network Shield is designed to the same
form factor as the Max32 board.

Features:

SMSC LAN8720 10/100 Ethernet PHY
RJ45 connector with integral magnetics
USB Device and Host Connectors
Two MCP2551 CAN Transceivers
Two 12-pin header connectors for CAN
Two I2C daisy chain connectors
256Kbit I2C EEPROM

32.768 Khz Oscillator

Doc: 502-211 page 1 of 11

Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.

chipKIT Network Shield Reference Manual

chipKIT Network Shield Hardware Overview

The Network Shield has the following hardware features:

1) USB Connectors
The connector on the top of the board is a standard USB A type receptacle. This is used

when the Max32/Network shield is used as a USB host. Immediately below this connector
is a USB Micro-AB connector. Tis connector is used when the Max32/Network Shield is
used as a USB device, or when using it as an On-The-Go (OTG) device.

2) Ethernet Connector with Integral Magnetics
This connector is used to connect the Max32/Network Shield to an Ethernet network..

3) JP4 – USB Host Connector Selection
When the Max32/Network Shield is used as a USB host, this jumper is used to select

which USB connector is being used.

4) J17 – Power Pass-through Connector
This connector passes the power connector from the Max32 through the Network Shield

board, and powers the Network Shield from the Max32.

5) J9 & J12 – Analog Signal Pass-Through Connectors
These connectors pass the analog input pins on the Max32 through the Network Shield

board.

www.digilentinc.com page 2 of 11

Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.

chipKIT Network Shield Reference Manual

6) CAN2 Connector
This connector provides access to the signals for CAN2.

7) CAN1 Connector
This connector provides access to the signals for CAN1.

8) Digital Signal Connector
This connector provides most of the signals used by the Ethernet and USB interfaces from

the Max32 board to the Network Shield board. The remaining signals are passed through
the Network Shield.

9) J7 – I2C #1 Daisy Chain Connector
This is a 2x4 pin header connector that provides access to the I2C signals SDA and SCL

as well as power from the 3.3V power bus and ground. This can be used to extend the I2C
bus off of the board and to power external I2C device. Digilent has cables and a selection
of I2C peripheral modules that can be accessed using this connector.

10) J7 – I2C #2 Daisy Chain Connector
This is a 2x4 pin header connector that provides access to the I2C signals SDA and SCL

as well as power from the 3.3V power bus and ground. This can be used to extend the I2C
bus off of the board and to power external I2C device. The jumpers for disabling the on­board pull-ups are adjacent to this connector.

11) Digital Signal Connectors
Some of the signals used by the Network Shield are provided on these connectors. The

rest of the signals are passed through the Network Shield.

www.digilentinc.com page 3 of 11

Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.

chipKIT Network Shield Reference Manual

chipKIT Network Shield Hardware Description

Introduction

The following describes the hardware provided
by the Network Shield and its use. Appendices
at the end provide pin-out and connection
tables.

The Network Shield is designed to be used
with the chipKIT Max32 board. When used in
combination, the two boards provide the
necessary supporting hardware and
connectors to make use of all of the advanced
communications and networking features of
the PIC32MX795F512L microcontroller on the
Max32.

Ethernet Interface

The Network Shield provides the ability to
interface with 10Mbps or 100Mbps Ethernet
networks. The PIC32MX795 microcontroller on
the chipKIT Max32 board contains a 10/100
Ethernet Medium Access Controller (MAC).
The Network Shield provides an SMSC
LAN8720 Ethernet Physical Layer Transceiver
(PHY). Together, the MAC and PHY provide a
complete 10/100 Ethernet interface.

The RJ45 connector, J1, provides the physical
connection to an Ethernet network using a
standard Ethernet cable.

When the Ethernet controller is enabled in the
PIC32 microcontroller, it takes over the use of
a number of the microcontroller pins. All of the
signals from these pins are taken from
connector J10 on the Network Shield
(connector J8 on the Max32). Three of these
signals are also shared with connector J7 on
the Max32 and are analog pins A11, A12, and
A13. When the Ethernet interface on the
Network Shield is being used, these pins are
not available for other use, and nothing should
be connected to them to avoid interference
with the operation of the Ethernet interface.

All devices on an Ethernet network must have
a unique address. This address is used to
direct packets on the network to a specific
device and to identify the device that originated
a packet. An Ethernet MAC uses a 48-bit
address value, commonly called the ‘MAC

Address’. These address values are globally

unique to ensure that no two devices on a
network can have conflicting addresses. MAC
addresses are assigned by the IEEE. The
address to use with the Network Shield is
printed on a sticker attached to the bottom of
the board. The address is a twelve digit
hexadecimal number of the form:
00183Exxxxxx, where xxxxxx represents six
hexadecimal digits. This value is used to
initialize the Ethernet Controller MAC Station
Address registers in the Ethernet controller of
the PIC32MX795 microcontroller.

In order to connect to and operate with an
Ethernet network, the PIC32 microcontroller
must be running network protocol stack
firmware. Normally, the TCP/IP (Transmission
Control Protocol/Internet Protocol) network

protocol is used and “TCP/IP Stack” software

will be used. The Ethernet library provided for
use with the Network Shield board provides the
necessary stack support for use of the chipKIT
Max32/Network Shield from within the MPIDE
programming environment.

If the board is being used outside the MPIDE
programming environment, The Microchip
Applications Library, available for download
from the Microchip web site provides full
protocol stack support compatible with the
PIC32MX795 MAC and the LAN8720 PHY.
Microchip also provides numerous example
programs illustrating the use of their network
protocol stack for various applications.

When not using the either the chipKIT Ethernet
library or the Microchip network protocol stack,
refer to the manufacturer documentation for
the PIC32MX795 and LAN8720, plus network

www.digilentinc.com page 4 of 11

Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.