3.4.9 Wi-Fi/Bluetooth Module (Optional)
The user has the option to solder an ATWILC3000-MR110CA Wi-Fi/BT module with a chip antenna or an ATWILC3000-MR110UA Wi-Fi/BT module with a U.FL connector.
The ATWILC3000-MR110PA WLAN PHY is designed to achieve a reliable and power-efficient physical layer communication as specified by IEEE® 802.11 b/g/n in Single Stream mode with a 20-MHz bandwidth. Advanced algorithms are used to achieve maximum throughput in a real-world communication environment with impairments and interference. The PHY implements all required functions such as FFT, filtering, FEC (Viterbi decoder), frequency and timing acquisition and tracking, channel estimation and equalization, carrier sensing and clear channel assessment, as well as automatic gain control. The module is available in a fully certified, 22.428 x 17.732 mm, 36-pin module package. For more information about the ATWILC3000, refer to the product web page.
| PIO | Signal Name | Shared | Signal Description |
|---|---|---|---|
| PD5 | SDMMC2_WILC3000_DAT0_PD5 | – | SDIO data |
| PD6 | SDMMC2_WILC3000_DAT1_PD6 | – | SDIO data |
| PD7 | SDMMC2_WILC3000_DAT2_PD7 | – | SDIO data |
| PD8 | SDMMC2_WILC3000_DAT3_PD8 | – | SDIO data |
| PD3 | SDMMC2_WILC3000_CMD_PD3 | – | SDIO command |
| PD4 | SDMMC2_WILC3000_CK_PD4 | – | SDIO clock |
| PE4 | BT_TX_FLEXCOM0_IO1_PE4 | 40-pin RPi connector | Bluetooth serial TX (RX into SAMA7G5) |
| PE3 | BT_RX_FLEXCOM0_IO0_PE3 | 40-pin RPi connector | Bluetooth serial RX (TX from SAMA7G5) |
| PE6 | BT_RTS_FLEXCOM0_IO3_PE6 | 40-pin RPi connector | Bluetooth serial RTS |
| PE7 | BT_CTS_FLEXCOM0_IO4_PE7 | 40-pin RPi connector | Bluetooth serial CTS |
| PD2 | SDMMC2_WILC3000_RSTN_PD2 | – | Module reset |
| PD10 | WILC3000_INT_PD10 | – | Interrupt |
| PE0 | WILC3000_EN_PE0 | – | Chip enable |
Special care must be taken when powering the ATWILC3000 wireless module. Due to the nature of the wireless transmission, the module draws much current from its supply rail. In the worst-case scenario, the module can draw up to 300 mA.
To address this power consumption, the module is fitted with its own separate power supply, the MCP1725, which is a 500-mA low dropout (LDO) linear regulator that provides high current and low output voltages in a very small package. For more information about the MCP1725, refer to the product web page.
The MCP1725 was chosen because it can supply the current required by the module, and because it features a shutdown input pin (SHDN) and a power good output pin (PWRGD):
- The SHDN input allows to shut down the wireless module when unused, therefore saving power.
- The PWRGD output ensures that the ATWILC3000 wireless module is kept in reset until its power rails are stable.