Initialization and configuration

It is recommended to reset WF200 before running the initialization phase described below. Initialization and configuration is performed by ::wf200_init. WF200 initialization phase is as follows:

• Bus configuration (SPI or SDIO)
• WF200 initialization
• Firmware download
• Receive startup indication
• PDS configuration

1. Bus configuration

The bus configuration is handled by ::wf200_init_bus. It has a specific implementation depending on the bus used.

SPI bus

During the SPI initialization, the host follows the steps below:

• Reset WF200
• Read the configuration register to make sure the communication with WF200 is available.
• Write the configuration register with the SPI bus configuration settings preferred (e.g. word mode, high frequency SPI enabled...).

SDIO bus

During the SPI initialization, the host follows the steps below:

• Send SDIO command 0

  Warning

  It is required for the host to wait a response from this command before issuing another command.

• Send SDIO command 8
• Send SDIO command 3
• Send SDIO command 7
• Enable function 1/cmd 53 in CCCR register .
• Enable interrupt.
• Configure the SDIO bus to function in 4-bit mode.
• Switch to high-speed mode (up to 50MHz).
• Set the block size used by the host in the FBR register .

2. WF200 initialization

The WF200 initialization is handled by ::wf200_init_chip. During this phase, the host interacts with WF200 registers described in wf200_registers.

• The first step performed is to set the correct values in the General purpose registers. Those values are linked to the crystal used by the hardware.
• Set the wake-up bit (bit 12) in the control register .
• Wait for the wlan_rdy bit (bit 13) to be set in the control register .
• Check if the access mode bit (bit 10) in the configuration register is at 1 (direct access mode).

3. Firmware download

First, the WF200 clock is enabled in ::wf200_download_run_bootloader and an optional test to verify the SRAM access is performed.

The firmware download is handled by ::wf200_download_run_firmware. A firmware binary needs to be loaded to the chip at power-up. The binary is signed and encrypted. This binary file is stored in a c table in wfm_wf200_XX.h (XX depending on the keyset used by WF200). Below is a diagram listing the steps followed by ::wf200_download_run_firmware to load the firmware.

After the host notifies the "OK_TO_JUMP" state, the WF200 will issue a startup indication when ready.

4. Startup indication

If the initialization process has been successful up to now the host should receive the startup indication from WF200.

The start up indication is described in the HiStartupIndBody_t structure.

5. PDS configuration

Once the startup indication received, the host can send to WF200 the PDS configuration (Platform Data Set). The PDS contains information regarding the WF200 environment. Below are some examples:

• IO configuration
• XTAL tune
• TX power control
• RF output configuration
• ...

The PDS is sent using a dedicated function wf200_send_configuration . The PDS presents itself in the FMAC driver as several string tables found in wf200_pds.c. Those tables are the results of the compression of a more complete and readable file. You can find more information on the PDS in a dedicated page wf200_pds.