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
UG407: WFM200S Wi-Fi
®
Expansion Kit User's Guide
WFM200S Wi-Fi NCP Expansion Kit
silabs.com
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