ELRS 3.6.2+ STM32L432 SX1280 dual diversity firmware

This is firmware for an RX or TX based on the ELRS 3.x.x maintenance branch but with support for dual diversity using an STM32L432 MCU.

If this is useful and/or you use it, please consider supporting my work here: https://ko-fi.com/dominicclifton

Schematic

Schematic attached for the RX, TX is the same except for the transmitter connection.

Flashing

1. put the STM32L432 in STM32 bootloader mode (using the BOOT0 pin + 10K to 3v3 or hold the BOOT0 button, then power on the board.
2. Use STM32CubeProgrammer and connect via the SWD pins.
3. Flash bootloader.
4. Flash firmware.

RX

• Flash BL/sx1280_rx_dual_diversity_bootloader.bin at address 0x08000000
• Flash ELRS/firmware.bin at address 0x08004000
• Future firmware can be uploaded via the FC (e.g. betaflight) passthough systems as required.

TX

• Flash BL/sx1280_tx_dual_diversity_bootloader.bin at address 0x08000000
• Flash ELRS/firmware.bin at address 0x08004000
• Future firmware can be uploaded via the EdgeTX passthough system as required.

Additionally the archives contain the .map and .elf files for the firmware for those interested, and in the ELRS-debug directories you can find builds compiled with some debug logging enabling, use the UART pins to see the output, this is useful to verify your RX/TX is functioning correctly.

Discussion

There is a thread on the ELRS discord server, here: https://discord.com/channels/596350022191415318/1460948337128898582

You can find me there as Hydra.

Notes

experimental release which uses full duplex on the TX, using UART1 on PA9/PA10. normally the code is built for a TX that uses a single half-duplex pin for the S.Port JR-bay connection.

See -DUSE_TX_FULLDUPLEX in the user_defines.txt (included in the .zip file) and source.