btstack/port/stm32-l476rg-nucleo-sx1280/README.md

# BTstack Port with Cinnamon for Semtech SX1280 Controller on STM32L476 Nucleo 

*Cinnamon* is BlueKitchen's minimal, yet robust Controller/Link Layer implementation for use with BTstack.

In contrast to common Link Layer implementations, our focus is on a robust and compact implementation for production use,
where code size matters (e.g. current code size about 8 kB).

## Overview

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 the SPI driver that uses DMA for full packets.

## Status

Tested with the[Miromico FMLR-80-P-STL4E module](https://miromico.ch/portfolio/fmlr-8x-x-stlx/) 
(see port/stm32-l451-miromico-sx1280) and the
[STM32 L476 Nucleo dev kit](https://www.st.com/en/evaluation-tools/nucleo-l476rg.html)
with our [SX1280 Shield](https://github.com/bluekitchen/sx1280-shield). 

SEGGER RTT is used for debug output, so a Segger J-Link programmer is required, but the on-board
[ST-Link programmer and debugger](https://www.st.com/en/development-tools/st-link-v2.html) can be replaced by an
[SEGGER J-Link OB](https://www.segger.com/products/debug-probes/j-link/models/other-j-links/st-link-on-board/). 

Uses 32.768 kHz crytstal as LSE for timing

Support for Broadcast and Peripheral roles.

The Makefile project compiles gatt_counter, gatt_streamer_server, hog_mouse and hog_keyboard examples.

## Limitation

### Advertising State:
- Only Connectable Advertising supported
- Only fixed public BD_ADDR of 33:33:33:33:33:33 is used

### Connection State:
- 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 16-bit tick time is provided by LPTIM1 based on 32768 Hz LSE.

## Getting Started

Just run make. You can upload the EXAMPLE.elf file created in build folder, 
e.g. with Ozone using the provided EXAMPLE.jdebug, and run it.

## TODO

### General
- indicate random address in advertising pdus
- allow to set random BD_ADDR via HCI command and use in Advertisements
- support other regular adv types
- 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

![STM32 L476RG Nucleo with SX1280 Shield](nucleo-with-sx1280-shield.jpg)
port: copy edit port readmes, archive ios port 2021-05-31 13:26:07 +00:00			`# BTstack Port with Cinnamon for Semtech SX1280 Controller on STM32L476 Nucleo`
ports: new stm32-l476rg-nucleo-sx1280 port 2020-10-13 22:26:03 +00:00
			`Cinnamon is BlueKitchen's minimal, yet robust Controller/Link Layer implementation for use with BTstack.`

			`In contrast to common Link Layer implementations, our focus is on a robust and compact implementation for production use,`
			`where code size matters (e.g. current code size about 8 kB).`

			`## Overview`

			`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 the SPI driver that uses DMA for full packets.`

			`## Status`

			`Tested with the[Miromico FMLR-80-P-STL4E module](https://miromico.ch/portfolio/fmlr-8x-x-stlx/)`
			`(see port/stm32-l451-miromico-sx1280) and the`
			`[STM32 L476 Nucleo dev kit](https://www.st.com/en/evaluation-tools/nucleo-l476rg.html)`
			`with our [SX1280 Shield](https://github.com/bluekitchen/sx1280-shield).`

			`SEGGER RTT is used for debug output, so a Segger J-Link programmer is required, but the on-board`
			`[ST-Link programmer and debugger](https://www.st.com/en/development-tools/st-link-v2.html) can be replaced by an`
			`[SEGGER J-Link OB](https://www.segger.com/products/debug-probes/j-link/models/other-j-links/st-link-on-board/).`

			`Uses 32.768 kHz crytstal as LSE for timing`

			`Support for Broadcast and Peripheral roles.`

			`The Makefile project compiles gatt_counter, gatt_streamer_server, hog_mouse and hog_keyboard examples.`

			`## Limitation`

			`### Advertising State:`
			`- Only Connectable Advertising supported`
			`- Only fixed public BD_ADDR of 33:33:33:33:33:33 is used`

			`### Connection State:`
			`- 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 16-bit tick time is provided by LPTIM1 based on 32768 Hz LSE.`

			`## Getting Started`

			`Just run make. You can upload the EXAMPLE.elf file created in build folder,`
			`e.g. with Ozone using the provided EXAMPLE.jdebug, and run it.`

			`## TODO`

			`### General`
			`- indicate random address in advertising pdus`
			`- allow to set random BD_ADDR via HCI command and use in Advertisements`
			`- support other regular adv types`
			`- 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`

			`![STM32 L476RG Nucleo with SX1280 Shield](nucleo-with-sx1280-shield.jpg)`