RIOT/boards/lora-e5-dev/doc.md

@defgroup boards_lora-e5-dev LoRa-E5 Development Board - STM32WLE5JC @ingroup boards @brief Support for the LoRa-E5 Development Board - STM32WLE5JC.

@warning This BOARD comes with arduino style pin headers, but the gpio mapping does not map to arduino BOARDs, even 3.3V and 5V pins are placed differently, so don't use arduino expansion-boards since these might short-circuit the mcu and/or expansion-board.

The LoRa-E5 Dev Board is an evaluation board for the Seeed Studio LoRa-E5 STM32WLE5JC module. The cpu includes a radio supporting multiple LPWAN protocols in the 868/915 MHz frequency bands, including LoRa, capable of 20.8dBm output at 3.3V.

Convenient interfaces as Grove and RS-485 are mapped out, and the many pins map most of the modules GPIOs. But watch out! Although it features Arduino style pin headers, they are not arduino compatible.

The board also includes a JST battery connector as well as control over the external power lines which can be enabled or disabled by software.

MCU

MCU	STM32WL5EJC
Family	ARM Cortex-M4
Vendor	ST Microelectronics
RAM	64KiB
Flash	256KiB
Frequency	up to 48MHz
FPU	no
Vcc	1.8 V - 3.6V
Datasheet	Datasheet
Reference Manual	Reference Manual
Board Manual	Board Manual
Board Schematic	Board Schematic
LoRa-E5 STM32WL5EJC Module wiki	https://wiki.seeedstudio.com/LoRa-E5_STM32WLE5JC_Module/#2-develop-with-stm32cube-mcu-package

Pinout

The default Peripheral Mapping is specified here

Board Interface

3 Buttons:

NAME	BOOT	D0	RESET
Pin	PA0 (IN)	PB13 (IN)	NRST

1 LED:

NAME	D5
Color	red
Pin	PB5

Power Lines

All power lines are on by default, but some of them can optionally be disabled, namely 3.3V and 5V. These feed all external pins as well as the internal LM75A, more details are available on the schematic.

Name	Controlled By	Alias
3.3V	PA9	LORA_E5_DEV_3P3V_ENABLE_PIN
3.3V	PB10	LORA_E5_DEV_5V_ENABLE_PIN

Flashing

Disabling Read Protection

The board comes pre-flashed with a DFU bootloader, an AT command Firmware and read protection enabled and set to 1. So before being able to program anything else, read protection needs to be set back to level 0.

The easiest way of doing this is with the STM32CubeProgramer GUI and setting the RDP option byte to AA

Alternatively you can use the STM32_Programer_CLI:

$ STM32_Programmer_CLI --connect port=swd --readunprotect

Programming with an external ST-LINK

Since there is no ST-LINK programmer on the board an external one needs to be connected. Any Nucleo or STM32Discovery board can be used for this by simply removing the ST-LINK jumpers and connecting on the CN4 headers (see UM1724 6.2.4 for more details). An example is seen in the following image:

     CN4                                       LoRa-E5 Dev
                                            (Dark Blue Header)
Pin 1: VDD_TARGET            N/C
Pin 2: SWCLK      ---->  Yellow Cable ---->       CLK
Pin 3: GND        ---->  Black Cable  ---->       GND
Pin 4: SWDIO      ---->  Blue Cable   ---->       DIO
Pin 5: NRST                  N/C
Pin 6: SWO                   N/C

Flashing can then be performed seamlessly with OpenOCD:

BOARD=lora-e5-dev make flash

Serial connection

The default serial connection is through the USB-C port mapping to PB7 (RX) and PB6 (TX) UART pins (a second UART and an LPUART interface is also exposed).

BOARD=lora-e5-dev make term

Debugging

For Debugging an external programmer is required, connected as depicted in the above picture, then the debugger can be attached with:

BOARD=lora-e5-dev make debug

LoRa

This board comes embedded with an sx126x based LoRa radio. The precise module that needs to be selected is USEMODULE += sx126x_stm32wl, this is also selected with USEMODULE += netdev_default.

Differently from other stm32wl chips this module only transmits through RFO_HP.

Sensors

This board includes a @ref drivers_lm75 temperature sensor. It can be included with USEMODULE += lm75a or through USEMODULE += saul_default.