This port targets the Semtech SX1280 radio controller. The Host Stack and the Controller (incl. Link Layer) run on a STM32 MCU, with the SX1280 connected via SPI.

It uses the SX1280 C-Driver from Semtech to communicate with the SX1280. The main modification was to provide an optimized polling SPI driver that is faster then the one provided by STM32CubeMX.

Status

Only tested with the Miromico FMLR-80-P-STL4E module so far. On this module, the 52 Mhz clock for the SX1280 is controlled by the MCU.

Segger RTT is used for debug output, so a Segger J-Link programmer is required.

Uses 32.768 kHz crytstal as LSE for timing

Support for Broadcaster and Peripheral roles.

The current Makefile project compiles the gatt_counter.c example.

Limitation

Advertising State:

Only advertises on Channel 37
Advertises as fast as possible, back to back
Only Connectable Advertising supported
Only fixed public BD_ADDR of 33:33:33:33:33:33 is used

Connection State:

Only a single packet is sent in each Connection Interval
Encryption not implemented
Some LL PDUs not supported

Central Role:

Not implemented

Observer Role:

Not implemented

Low power mode - basically not implemented:

MCU does not sleep
SPI could be disabled during sleep
1 ms SysTick is used for host stack although 64-bit tick time is provided from LPTIM1

Getting Started

For the FMLR-80-P-STL4E module, just run make. You can upload the .elf file created in build folder e.g. with Ozone using the provided stm32-sx1280.jdebug and run it.

TODO

General

advertise on all configured channels
only advertise with advertising interval
indicate random address in adertising pdus
allow to set random BD_ADDR via HCI command
handle Connection Param Update
multiple packets per connection interval
handle Encryption

Low Power

enter STANDY_RC mode when idle
implement MCU sleep (if next wakeup isn't immediate)
sleep after connection request until first packet from Central
replace SysTick with tick counter based on LPTIM1
disable SPI on MCU sleep