Silicon Laboratories WFM200S User Manual
UG407: WFM200S Wi-Fi® Expansion Kit
User's Guide
The WFM200S Wi-Fi Expansion Kit is an excellent way to explore and evaluate the WFM200S Wi-Fi Transceiver Module with
a Raspberry Pi or an EFM32 MCU for your embedded application.
The WFM200S Wi-Fi Transceiver Module is an easy to use and easy to interface Wi-Fi
Network Co-Processor (NCP). Most of the associated complexity of Wi-Fi and the protocol stack is offloaded to the NCP and allows for easy Wi-Fi integration into any embedded system.
The kit easily integrates and brings Wi-Fi connectivity to a compatible Silicon Labs
MCU Starter Kit through the EXP header. The WFM200S Wi-Fi Expansion Kit has also
been designed after the Raspberry Pi Hardware Attached on Top (HAT) board specification, allowing the WFM200S Wi-Fi Expansion Kit to connect to a Raspberry Pi.
WFM200S EXPANSION BOARD FEATURES
• Selectable SPI or SDIO host interface
• EXP connector for interfacing Silicon
Labs Starter Kits
• Allows board detection and
identification
• Raspberry Pi compatible HAT
• 40-pin header
• HAT EEPROM for identification
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Table of Contents
1. Introduction ................................3
1.1 Kit Contents ...............................4
2. Hardware Overview .............................5
2.1 Hardware Layout .............................5
3. WFM200S Wi-Fi NCP Expansion Kit .......................6
3.1 Host Interfaces ..............................6
3.2 Power-on and Manual Reset Circuit .......................7
4. Connectors ................................8
4.1 EXP Header ...............................9
4.1.1 Pass-through EXP Header ........................9
4.1.2 EXP Header Pinout ...........................10
4.2 Raspberry Pi Connector ...........................11
4.2.1 Raspberry Pi Connector Pinout .......................12
4.3 External FEM Connector ..........................13
4.3.1 External FEM Connector Pinout .......................13
4.4 PTA Connector ..............................14
4.4.1 PTA Connector Pinout ..........................14
4.5 Secondary RF Connector ..........................14
4.6 Power Supply ..............................15
5. Schematics, Assembly Drawings, and BOM ...................16
6. Kit Revision History ............................17
6.1 SLEXP8023A Revision History ........................17
6.2 SLEXP8023C Revision History ........................17
7. Document Revision History .........................18
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UG407: WFM200S Wi-Fi® Expansion Kit User's Guide
Introduction
1. Introduction
This user guide describes the WFM200S Wi-Fi Expansion Kit. The kit connects to either a Silicon Labs EFM32 MCU starter kit (STK), a
Silicon Labs EFR32 wireless starter kit (WSTK) or a Raspberry Pi equipped with the 40-pin Raspberry Pi hardware-attached-on-top
(HAT) connector. SDIO support is available only with selected hosts.
Figures 1.1 and 1.2 shows the kit connected to a Silicon Labs MCU STK through the Expansion Header and a Raspberry Pi, respectively.
Figure 1.1. WFM200S Wi-Fi Expansion Kit Connected to a Silicon Labs EFM32GG11 MCU STK
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UG407: WFM200S Wi-Fi® Expansion Kit User's Guide
Introduction
Figure 1.2. WFM200S Wi-Fi Expansion Kit Connected to a Raspberry Pi
Note: Do not connect the kit to both a Silicon Labs MCU STK and a Raspberry Pi at the same time.
1.1 Kit Contents
The WFM200S Wi-Fi Expansion Kit comes in two versions, which differs in what's included in the box:
• SLEXP8023A:
• BRD8023A WFM200S Wi-Fi EXP Board
• 8 GB Micro-SD card with software image for Raspberry Pi 2
• SLEXP8023C:
• BRD8023A WFM200S Wi-Fi EXP Board
• 8 GB Micro-SD card with software image for Raspberry Pi 2
• Raspberry Pi 2 Model B Single-Board Computer
• Raspberry Pi Power Supply 5.1 V, 2.5 A
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2. Hardware Overview
EXP-header for
Starter Kits
Power source
select switch
Pass-through EXP-header
Not mounted
WFM200S Wi-Fi Transceiver
Raspberry Pi connector
On bottom side
Current consumption
measurement header
Not mounted
WFM200S Wi-Fi
Expansion Board
Host interface
select switch
Secondary RF output
coaxial connector
TX/RX Activity LED
External FEM header
Not mounted
PTA header
Not mounted
Reset button
2.1 Hardware Layout
The layout of the WFM200S Wi-Fi Expansion Kit is shown in the figure below.
UG407: WFM200S Wi-Fi® Expansion Kit User's Guide
Hardware Overview
Figure 2.1. WFM200S Wi-Fi Expansion Kit Hardware Layout
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UG407: WFM200S Wi-Fi® Expansion Kit User's Guide
WFM200S Wi-Fi NCP Expansion Kit
3. WFM200S Wi-Fi NCP Expansion Kit
The WFM200S Wi-Fi Transceiver Module is a Wi-Fi Network Co-Processor (NCP) transceiver from Silicon Labs.
3.1 Host Interfaces
SPI and SDIO are the two available host interfaces (HIF) on the WFM200S Wi-Fi Expansion Kit. A slide switch, whose state is sampled
during power-on reset or manually issued reset is used to select the interface. The slide switch must remain in the same position
throughout the duration of the session since it also controls HIF selection multiplexer circuits.
When the WFM200S Wi-Fi Expansion Kit is connected to an EFM32/EFR32 starter kit through the EXP header, the state of the HIF
selection switch can be read (but not controlled) by the kit mcu through a GPIO pin.
The WFM200S Wi-Fi Expansion Kit incorporates a set of multiplexer circuits which allows the user to use the same kit for evaluating the
WFM200S in both applications requiring SPI or SDIO connectivity to the host. These circuits will normally not be needed in an end-user
application since in most cases the interface to use will be fixed.
A simplified circuit diagram showing the host interface multiplexer circuits is shown below. The EXP_HEADER9 signal is connected to
pin 9 on the EXP header, while the HIF_OEn output enable signal is controlled by the power-on reset circuit (explained later).
Figure 3.1. Host Interface Multiplexer Circuit
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