Silicon Laboratories Finland WF121 User Manual
WF121 Wi-Fi MODULE
DATA SHEET
Thursday, 12 July 2012
Version 1.2
Copyright © 2000-2012 Bluegiga Technologies
All rights reserved.
Bluegiga Technologies assumes no responsibility for any errors which may appear in this manual.
Furthermore, Bluegiga Technologies reserves the right to alter the hardware, software, and/or specifications
detailed here at any time without notice and does not make any commitment to update the information
contained here. Bluegiga’s products are not authorized for use as critical components in life support devices
or systems.
The WRAP, Bluegiga Access Server, Access Point and iWRAP are registered trademarks of Bluegiga
Technologies.
The Bluetooth trademark is owned by the Bluetooth SIG Inc., USA and is licensed to Bluegiga Technologies.
All other trademarks listed herein are owned by their respective owners.
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VERSION HISTORY
Version Comment
1.0 First version
1.1 FCC and IC information added
1.2 WF121-N layout guide
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TABLE OF CONTENTS
1 Ordering Information..................................................................................................................................... 7
2 Pin-out and Terminal Descriptions ............................................................................................................... 8
3 Power control .............................................................................................................................................. 10
3.1 Power supply requirements ............................................................................................................... 10
3.2 Reset .................................................................................................................................................. 10
4 Microcontroller ............................................................................................................................................ 11
5 Interfaces .................................................................................................................................................... 12
5.1 General Purpose I/O pins .................................................................................................................. 12
5.2 Serial ports ......................................................................................................................................... 12
5.3 I2C/SPI ............................................................................................................................................... 13
5.4 USB On-The-Go ................................................................................................................................ 13
5.5 Ethernet ............................................................................................................................................. 14
5.6 Analog inputs ..................................................................................................................................... 15
5.7 Timers ................................................................................................................................................ 15
5.8 Parallel master port ............................................................................................................................ 15
5.9 Microcontroller programming interface .............................................................................................. 15
5.10 RF Debug Interface ........................................................................................................................... 16
5.11 Bluetooth co-existence ...................................................................................................................... 16
5.12 CPU Clock ......................................................................................................................................... 17
5.13 32.768 kHz External Reference Clock ............................................................................................... 18
6 Example schematic .................................................................................................................................... 19
7 802.11 Radio .............................................................................................................................................. 20
7.1 Wi-Fi Receiver ................................................................................................................................... 20
7.2 Wi-Fi Transmitter ............................................................................................................................... 20
7.3 Antenna switch for Bluetooth coexistence ......................................................................................... 20
8 Firmware ..................................................................................................................................................... 21
9 Host interfaces ............................................................................................................................................ 23
9.1 UART ................................................................................................................................................. 23
9.2 USB .................................................................................................................................................... 23
9.3 SPI ..................................................................................................................................................... 23
10 Electrical characteristics ........................................................................................................................ 24
10.1 Absolute maximum ratings ................................................................................................................ 24
10.2 Recommended operating conditions ................................................................................................. 24
10.3 Input/output terminal characteristics .................................................................................................. 25
10.4 Digital ................................................................................................................................................. 25
10.5 Reset .................................................................................................................................................. 25
10.6 Power consumption (preliminary) ...................................................................................................... 26
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RF Characteristics ................................................................................................................................. 27
11
12 Physical dimensions .............................................................................................................................. 29
13 Layout guidelines ................................................................................................................................... 30
13.1 WF121-E ............................................................................................................................................ 30
13.2 WF121-N ............................................................................................................................................ 30
13.3 WF121-A ............................................................................................................................................ 31
13.4 Thermal considerations ..................................................................................................................... 32
13.5 EMC considerations ........................................................................................................................... 32
14 Soldering recommendations .................................................................................................................. 34
15 Certifications .......................................................................................................................................... 35
15.1 CE ...................................................................................................................................................... 35
15.2 FCC and IC ........................................................................................................................................ 35
15.2.1 FCC et IC ................................................................................................................................... 37
16 Qualified Antenna Types for WF121-E .................................................................................................. 40
17 Contact information ................................................................................................................................ 41
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DESCRIPTION
WF121 is a self-contained Wi-Fi module
providing a fully integrated 2.4GHz 802.11
b/g/n radio and a 32-bit microcontroller (MCU)
platform, making it an ideal product for
embedded applications requiring simple, lowcost and low-power wireless TCP/IP
connectivity. WF121 also provides flexible
interfaces for connecting to various
peripherals.
WF121 allows end user applications to be
embedded onto the on-board 32-bit
microcontroller either using a simple
BGScript
TM
scripting language or for more
sophisticated applications; ANSI C-language.
This cuts out the need of an external MCU
and allows the development of smaller and
lower-cost products. However WF121 can
also be used in modem-like mode in
applications where the external MCU is
needed.
With an integrated 802.11 radio, antenna,
single power supply, and regulatory
certifications, WF121 provides a low-risk and
fast time-to-market for applications requiring
Internet connectivity. This combined with
Bluegiga’s excellent customer service will turn
your Internet-of-Things applications into
reality.
APPLICATIONS:
KEY FEATURES:
2.4GHz band IEEE 802.11 b/g/n radio
Excellent radio performance:
TX power: +17 dBm
RX sensitivity: -97 dBm
Host interfaces:
20Mbps UART
USB on-the-go
Peripheral interfaces:
GPIO, AIO and timers
I2C, SPI and UART
Ethernet
Embedded TCP/IP and 802.11 MAC
stacks:
IP, TCP, UDP, DHCP and DNS
protocols
BGAPI host protocol for modem
like usage
BGScript
native C-development for self-
contained applications
32-bit embedded microcontroller
TM
scripting language or
PoS terminals
RFID and laser scanners
Wi-Fi internet radios and audio
streaming products
Wireless cameras
Video streaming
Portable navigation devices
Portable handheld devices
Wi-Fi medical sensors
Wireless picture frames
80Mhz, 128kB RAM and 512kB
Flash
MIPS architecture
Temperature range: -40
o
C - +85oC
Fully CE, FCC and IC qualified
PHYSICAL OUTLOOK:
WF121-A
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1 Ordering Information
Product code Description
WF121-A WF121 module with integrated antenna
WF121-E WF121 module with U.FL connector
WF121 module with RF pin.
WF121-N
DKWF121 WF121 development kit
Non-standard product, so minimum order quantity applies.
Please contact: sales@bluegiga.com
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Page 7 of 41
2 Pin-out and Terminal Descriptions
35
36
37
38
39
40
41
44
45
RD943RD7
46
RD10
47
RD1
48
GND
49
ANT
50
GND
GNDPAD
51
SPI_MISO53SPI_CLK54SPI_MOSI55SPI_CS
52
GND
42
RD6
BT_RF
RD5/BT_ACTIVE
GND
1
RD4/BT_STATUS
RD0/INT0/WLAN_DENY
RE1
RE0
RB15
2
4
3
RF5
RD11/INT4/BT_PERIODIC
RE3
RE2
5
7
6
Figure 1: WF121 pinout
26
27
28
29
30
31
32
33
34
RF4
RC14/SOSCO
VDD_PA
RE4
8
RC13/SOSCI
VDD_3.3V
9
RD2
RC15/OSC2
RE6
RE5
11
10
RD3
RC12/OSC1
RE7
12
RG2/D+
RB1/PGEC1
MCLR
14
13
GND
RG3/D-
RB0/PGED1
15
VBUS
RB5
RB10
RB11
RB12
RB13
RB14
RF3
RB8
16
25
24
23
22
21
20
19
18
17
GND
Pad number Function Description
9 VDD_3.3V Module power supply
8 VDD_PA RF power amplifier power supply
1, 16, 26, 45,
48, 50
51 GNDPAD
40 BT_RF
GND
Ground, connected together internally but should all be connected directly to a solid ground plane
Thermal ground pad, should be soldered to a directly to a solid ground plane for improved thermal
conductance
Bluetooth coexistence antenna connection, connect to ground through a 51ohm resistor if
coexistence is not used
49 ANT Antenna connection pad in N variant of the module, in other variants not connected
25 VBUS USB VBUS input
Module reset, also used for programming using a Microchip tool. Internal pull-up, can be left
13 MCLR
floating or connected to ground through a 100nF capacitor for delayed power-up reset (note:
Microchip ICSP programming tools will not work with a capacitor)
Table 1: Single function pad descriptions
PAD# GPIO I2C SPI UART Ethernet Timer USB Analog Prog. Parallel Other
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Page 8 of 41
2
3 RE0
4 RE1
5 RE2
6 RE3
7 RE4
10 RE5
11 RE6
12 RE7
14
15
17 RB8
18 RF3 OTG_ID
19 RB14
20 RB13
21 RB12
22 RB11
23 RB10
24
27 RG3
28 RG2
29 RD3 SCL3 SDO3 U1TX OC4
30 RC12
31 RC15
32 RD2 SDA3 SDI3 U1RX OC3
33
34
35
36
37
38
39 RD4
41 RD5
42
43
44
46
47 RD1 SCK3
RB15
CN12
RB1
CN3
RB0
CN2
RB5
CN 7
RC13
CN 1
RC14
CN0
RF4
CN17
RF5
CN18
RD11
INT4
RD0
INT0
RD6
CN15
RD7
CN16
RD9
INT2
RD10
INT3
U2CTS
SS4
SCK4
SDA5 SDI4 U2RX
SCL5 SDO4 U2TX
SDA1 SS3
SCL1 IC3 PMA15
U5RX
U2RTS
U5TX
U1CTS
U4RX
U1RTS
U4TX
EMDC OCFB
ERXD1 PMD0
ERXD0 PMD1
ECRSDV PMD2
EREFCLK PMD3
ERXERR PMD4
ETXEN PMD5
ETXD0 PMD6
ETXD1 PMD7
C1OUT
T1CK
IC4
OC1
IC5/OC5 PMWR BT_STATUS
ETXERR
IC2
EMDIO OC2
VBUSON AN5
D-
D+
AN15
AN1 PGEC1
AN0 PGED1 PMA6
AN8
AN14
AN13 TDI PMA10
AN12 TCK PMA11
AN11 TDO PMA12
AN10 TMS PMA13
PMA0
PMLL
PMA1
PMALH
PMA9
PMA8
PMA14 BT_PERIODIC
PMRD BT_ACTIVE
OSC1
OSC2
SOSCI
SOSCO
WLAN_DENY
Table 2: Multifunction pad descriptions
Note: 5V tolerant pads are marked with orange. CN pins support pull-up, pull-down and GPIO notifications
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Page 9 of 41
3 Power control
3.1 Power supply requirements
WF121 is designed to operate with a 3.3V nominal input voltage supplied to two module pads. The VDD_3.3V
pad can be fed with a voltage between 2.3V and 3.6V and is used to power the internal microcontroller. The
VDD_PA pad can be supplied with a voltage between 2.7V and 4.8V and supplies the RF power amplifier and
the internal switch-mode converter powering the WiFi digital core.
In lithium battery powered applications, VDD_PA can be connected directly to the battery, while a regulator is
needed to supply the VDD_3.3V with a lower voltage, as needed by the design.
The VDD_PA supply should be capable of providing at least 350mA, though the average consumption of the
module will be much less than that. The VDD_3.3V supply will draw a peak current of less than 100mA, not
including current drawn from the GPIO pins. The PA supply should preferably be bypassed with a 10 to 100µF
capacitor to smooth out the current spikes drawn by the Wi-Fi power amplifier. External high frequency
bypassing is not needed, the module contains the needed supply filtering capacitors.
While the Wi-Fi power saving modes reduce the idle consumption to very low levels, it may in some
applications be useful to reduce the consumption even further. For this purpose, the Wi-Fi part of the module
can be fully shut down internally by disabling the internal switch mode converter to minimize power
consumption, though restarting it requires a new WiFi core power-up initialization. This will usually take
several seconds, but in applications where a connection is required only once a few minutes or this might not
be an issue while the reduced consumption can be very valuable.
The WF121 module automatically applies various power saving modes during operation to minimize average
power consumption.
3.2 Reset
WF121 can be reset by the MCLR-pin (active low), system power up, the internal brown-out detector or the
internal watchdog timer.
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Page 10 of 41
4 Microcontroller
WF121 contains a Microchip PIC32-series microcontroller with a MIPS M4K core. At a maximum clock
frequency of 80 MHz the core can reach a performance of 125 DMIPS while keeping low power consumption.
The microcontroller used in WF121 contains 512kB of Flash memory and 128kB of SRAM.
Most peripheral features are directly provided by the microcontroller and for low level information and detailed
descriptions please refer to the material and datasheets of the PIC32MX695H.
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Page 11 of 41
5 Interfaces
5.1 General Purpose I/O pins
To see which GPIOs are multiplexed with which features, please refer to Table 2.
.WF121 contains a number of pads that can be configured to be used as general purpose digital IO’s, analog
inputs or for various built-in functions. Provided functions include a Full Speed USB-OTG port, three I2C-ports,
two SPI-ports, two to four UART’s, Ethernet MAC with RMII connection and various timer functions. Some of
the pads are 5V tolerant. All GPIO pads can drive currents of up to +/- 25 mA.
Four pins are available for implementing a coexistence scheme with a Bluetooth device. The exact order and
function as well as the coexistence system desired is software configurable, with the default pad bindings
shown in Table 3 for a Unity-3e+ coexistence scheme. If the pads are bound to WiFi chip pins, the CPU pins
associated with the pads must be set to inputs.
5.2 Serial ports
Pad number UART 1 UART 2 UART 4 UART 5
17 CTS RX
21 RTS TX
29 TX
32 RX
35 RX
36 TX
44 CTS RX
47 RTS TX
Table 3: Serial port pads
Two UART’s are provided with RTS/CTS-handshaking. If handshaking is not needed, up to four UART’s can
be implemented. Speeds up to 20 Mbps are possible, but the higher bit rates might require the use of an
external crystal for sufficient clock accuracy. The serial ports can also be used as host connections when
using an external microcontroller.
To see what other functions are present on the same pins, please refer to Table 2.
.
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Page 12 of 41
5.3 I2C/SPI
Pad number I2C SPI
17 SS4 – Slave select SPI 4
19 SCK4 - Clock SPI 4
29 SCL3 – Clock I2C 3 SDO3 – Data out SPI 3
32 SDA3 – Data I2C 3 SDI3 – Data in SPI 3
35 SDA5 – Data I2C 5 SDI4 – Data in SPI 4
36 SCL5 – Clock I2C 5 SDO4 – Data out SPI 4
46 SCL1 – Clock I2C 1
44 SDA1 – Data I2C 1 SS3 – Slave select SPI 3
47 SCK3 – Clock SPI 3
Table 4: Pads for I2C and SPI
Up to three I
together and with the UART signals. The I
the SPI can be operated at up to 40 Mbps. The SPI ports are also available for use as a host connection for
use with an external microcontroller.
To see what other functions are present on the same pins, please refer to Table 2.
2
C-ports and up to two SPI ports can be implemented, mostly multiplexed on the same pins
2
C ports support 100 kHz and 400 kHz speed specifications, while
5.4 USB On-The-Go
Pad number Function Description
18 OTG_ID USB-OTG mode identify line
25 VBUS USB bus supply input
27 D- Data +
28 D+ Data -
26 VBUSON USB bus supply switch enable in host mode
Table 5: USB pads
The module contains a USB-OTG system with an integrated transceiver. Full Speed (12 Mbps) USB 2.0
profile is supported in device mode, while the host system can operate in Low Speed and Full Speed modes.
For host use an external switch can be implemented to provide switched power for the connected device. Pad
number 26 can be dedicated to control this switch. The USB device can be used as a host connection,
although the embedded (simplified) USB-OTG may not be able to support every kind of USB system, like
hubs.
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