Radio Platform Notes

EMW3165 Radio Platform Notes

Rewair uses WICED 3.3.1 with a custom AWAIR platform overlay. The tracked application and platform sources are synchronized into the sibling WICED SDK checkout by the repository build scripts; see Building and Flashing.

Platform differences

The WICED reference platform is a BCM943362WCD4 with an STM32F205. The Awair radio module is an EMW3165 with an STM32F411, so Rewair overrides the MCU layout, pins, flash handling, and idle behavior.

Function	STM32F411 pins	Notes
F103 sensor link	PA2 TX / PA3 RX	USART2, 115200 8N1
BI201 Bluetooth	PB6 TX / PA10 RX	USART1, 115200 8N1
F103 reset	PB12	Active sequencing is handled by the bridge
SPI-flash CS	PA15	Software-controlled, active low
SPI1	PB3 SCK / PB4 MISO / PA7 MOSI	Mapping from the EMW3165 datasheet

The SPI pins differ from the WICED reference design. PA15, PB3, and PB4 also carry full-JTAG functions, but the board uses SWD on PA13/PA14, so the SPI assignment does not block normal debugging. The flash map and tooling are documented in SPI Flash and Recovery.

Firmware constraints

• F411 internal flash is 512 KiB. The Rewair application occupies sectors 3–7; the OTA bootloader uses an F411-specific erase path because the generic WICED F4 helper continues into nonexistent sectors on this part.
• DCT occupies the internal sectors between the bootloader and application. Normal build, release-install, and flash scripts preserve it unless a reset is explicitly requested.
• WICED_DISABLE_MCU_POWERSAVE keeps SysTick active in the ordinary WFI idle path. The SDK's tickless path was observed missing a short wake-up and later tripping the watchdog.
• USART1 stdio is disabled because the BI201 owns that peripheral. Runtime diagnostics use SWD-readable state instead of the old serial console.

Low-level diagnostics

tools/legacy/emw3165_sensor_console is a small bare-metal application that talks to the F103 without starting WICED or Wi-Fi. Use it to distinguish a sensor-protocol problem from the WICED UART/DMA path. Current investigation state belongs in Project Status, not on this platform page.