Digilent 410-231P User Manual

chipKIT™ WiFi Shield Reference

Manual

Revision: February 7, 2013
Note: This document applies to REV C of the board.

Overview

The chipKIT™ WiFi Shield is an interface
board designed for use with Digilent’s chipKIT
line of microcontroller boards such as the
Uno32™, uC32™, or Max32™. The chipKIT
line is a family of microcontroller boards based
on the high performance Microchip PIC32
family of microcontrollers.

The chipKIT WiFi Shield provides chipKIT
microcontroller boards the ability to connect to
and communicate with IEEE 802.11
compatible wireless networks.

The WiFi Shield also provides a micro-SD card
connector for use with micro-SD flash memory
cards. The chipKIT MPIDE SD library can be
used to read/write files stored on the micro-SD
card.

The WiFi Shield is intended for use with the
Digilent network libraries, DNETcK and
DWIFIcK, available for free download from the
Digilent web site. These libraries make use of
and include a custom version of the Microchip
Applications Library licensed from Microchip.

Early versions of the WiFi Shield use the
Microchip MRF24WB0MA WiFi module. Later
versions use the improved MRF24WG0MA
WiFi module.

Features include:

• IEEE 802.11b/g-compliant RF
transceiver

• serialized unique MAC address

• data rates up to 11Mbps for 802.11b

and 54Mbps for 802.11g possible

• WEP, WPA-PSK, WPA2-PSK security

• integrated PCB antenna

• radio regulation certification for the

United States (FCC), Canada (IC), and
Europe (ETSI)

• micro SD card connector

• four user accessible LEDs

1300 NE Henley Court, Suite 3

Pullman, WA 99163

[phone] Voice | [phone] Fax

chipKIT WiFi Shield with
MRF24WB0MA WiFi Module

chipKIT WiFi Shield with
MRF24WG0MA WiFi Module

Doc: 502-231 page 1 of 4

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

chipKIT™ WiFi Shield Reference Manual

Functional Description

Overview

Depending on the production version, the
chipKIT WiFi Shield provides support for either
IEEE 802.11b or IEEE 802.11b/g wireless
networks. It is compatible with 802.11b/g/n
networks, and is designed for use with
chipKIT™ and chipKIT™ compatible
microcontroller boards.

The initial production version of the WiFi Shield
uses the Microchip MRF24WB0MA WiFi
module. This modules supports IEEE 802.11b
networks at 1 and 2 Mbps data rates.

Later productions versions of the WiFi Shield
use the improved Microchip MRF24WG0MA
module. This module provides IEEE 802.11b/g
support for embedded applications at data
rates of 1, 2, 5.5 and 11 Mbps for 802.11b or 6,
9, 12, 18, 24, 36, 48, and 54 Mbps for 802.11g.

The production version of the board can be
determined by reading the part number of the
MRF24Wx0MA module from the sticker or
engraved on the metal shield of the module.

The WiFi Shield is intended to be used with the
Digilent network libraries, DNETcK and
DWIFIcK, available for free download from the
Digilent web site. The DNETcK and DWIFIcK
libraries are intended for use with the chipKIT
MPIDE development environment. These
libraries contain Microchip Applications Library
code licensed for use by Digilent from
Microchip.

To use the chipKIT WiFi Shield outside of the
MPIDE development environment, the
Microchip Applications Library, available from

www.microchip.com, can be used as a starting

point to create custom library code to work with
the WiFi Shield.

The WiFi shield also provides a micro-SD card
connector and four discrete LEDs. The micro­SD card connector provides the ability to
access files stored on a micro-SD size flash

memory card using the chipKIT MPIDE SD
library.

The discrete LEDs are connected to four digital
I/O pins on the chipKIT microcontroller board
and can be accessed using the pinMode()
and digitalWrite() functions in the MPIDE
software.

Refer to the chipKit WiFi Shield schematic,
available on the Digilent web site, for detailed
information about the circuits on the board.

802.11b/g Interface

The 802.11b/g compatible WiFi interface on
the chipKIT WiFi Shield is provided by a
Microchip MRF24Wx0MA WiFi module. This
module provides the radio transceiver,
antenna, and 802.11 compatible network
firmware.

The MRF24Wx0MA firmware provides the

802.11 network protocol software support. The
DNETcK and DWIFIcK libraries provide the
TCP/IP network protocol support that works
with the 802.11 protocol support provided by
the WiFi module.

The primary communications interface with the
WiFi module is a 4 wire SPI bus. The
MRF24Wx0MA WiFi module supports SPI
clock speeds up to 25MHz. An active low
RESET signal can be used to reset the WiFi
module, and an external interrupt signal, INT,
is used by the module to signal to the host
microcontroller that it needs servicing by the
microcontroller software.

The MRF24Wx0MA provides the following
additional control signals: write protect (WP);
HIBERNATE; RESET; and INT.

More detailed information about the operation
of the MRF24Wx0MA can be obtained from the
manufacturer data sheet available from the
Microchip web site.

www.digilentinc.com page 2 of 4

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