MRF24WB0MA Datasheet, PDF (7/34 Pages) Microchip Technology – 2.4 GHz, IEEE Std. 802.11b™ RF Transceiver Module

MRF24WB0MA/MRF24WB0MB
1.0 DEVICES OVERVIEW
The MRF24WB0MA and MRF24WB0MB are low-
power, 2.4 GHz, IEEE Std. 802.11-compliant, surface
mount modules with all associated RF components –
crystal oscillator, bypass and bias passives with inte-
grated MAC, baseband, RF and power amplifier, and
built-in hardware support for AES, and TKIP (WEP,
WPA, WPA2 security). The integrated module design
frees the designer from RF and antenna design tasks
and regulatory compliance testing, ultimately providing
quicker time to market.
The MRF24WB0MA module is approved for use with
the integrated PCB meander antenna.
The MRF24WB0MB comes with an ultra miniature
coaxial connector (U.FL) and is approved for use with
a list of pre-certified antennas. See Section 2.8
“External Antenna”, for specific recommendations.
The MRF24WB0MA/MRF24WB0MB modules are
designed to be used with Microchip’s TCP/IP software
stack. The software stack has an integrated driver that
implements the API that is used in the modules for
command and control, and for management and data
packet traffic.
The Microchip TCP/IP software stack is available in the
free Microchip Application Libraries download (includ-
ing example applications and source code) from the
Microchip web site, http://www.microchip.com/wireless
The combination of the module and a PIC running the
TCP/IP stack results in support for IEEE Standard
802.11 and IP services. This allows, for example, the
immediate implementation of a wireless web server.
The MRF24WB0MA/MRF24WB0MB modules have
received regulatory approvals for modular devices in
the United States (FCC), Canada (IC), and Europe
(ETSI). The modular approval removes the need for
expensive RF and antenna design, and allows the end
user to place the modules inside a finished product and
not require regulatory testing for an intentional radiator
(RF transmitter). They also have Radio Type Approval
Certification for Japan. See Section 3.0 “Regulatory
Approval”, for the specific requirements that should be
adhered to by the integrator.
1.1 Interface Description
The block diagram in Figure 1-1 represents a
MRF24WB0MA/MRF24WB0MB module. It interfaces
to a Microchip PIC18, PIC24, dsPIC33, or PIC32 micro-
controllers via a four-wire serial slave SPI interface –
interrupt, hibernate, Reset, power and ground signals.
The module runs on a single supply voltage of nomi-
nally 3.3v. It also supports optional JTAG and serial
debug for testability. The debug port operates at 3.3v
and requires a level shifter for operation with RS-232
devices. Figure 1-2 shows a simplified example con-
nection between a Microchip PIC MCU and the mod-
ule. Table 1-1 lists the pin descriptions.
Data communications with the MRF24WB0MA/
MRF24WB0MB are through the SPI interface that is
detailed in Section 2.0 “Circuit Description”. The
Microchip PIC microcontroller communicates with the
module via a command API from within the Microchip
TCP/IP stack. The command API is detailed in the
Microchip TCP/IP Stack online help that is included in
the free Microchip Application Libraries download.
FIGURE 1-1:
MRF24WB0MA/MRF24WB0MB BLOCK DIAGRAM
MRF24WB0MA 2. 4 GHz IEEE Std. 802.11b RF Transceiver Module
FLASH
PCB
Antenna
(MRF24WB0MA)
Matching
Circuitry
AES, TKIP
Encryption
Accelerator
2.4 GHz
Transceiver
Interface
RAM
Power
Amplifier
ROM
SPI
Digital I/O
Interrupt
Power
JTAG
Debug
Reset
Hibernate
 2010 Microchip Technology Inc.
Preliminary
DS70632A-page 7