STM32L1 Discovery

Overview

The two generations of the STM32L1 Discovery development boards come with an integrated ST-LINK/V2 debugger and programmer. The boards have a 24-segment LCD and a touch slider, along with two user LEDs and a user button. Support circuitry for measuring power consumption is also available. It also comes with a comprehensive STM32 software HAL library and various packaged software examples.

There are two variants of the board:

STM32LDISCOVERY targets STM32L152RBT6, with 128K flash, 16K RAM, 4K EEPROM
STM32L152CDISCOVERY targets STM32L152RCT6, with 256K flash, 32K RAM, 8K EEPROM

The STM32LDISCOVERY is no longer sold, but was widely available. stm32l1_disco configuration enables support for STM32LDISCOVERY board and stm32l152c_disco configuration enables support for STM32L152CDISCOVERY board.

More information about the board can be found at the STM32LDISCOVERY website [1].

Hardware

The STM32 Discovery board features:

On-board ST-LINK/V2 with selection mode switch to use the kit as a standalone ST-LINK/V2 (with SWD connector for programming and debugging)
Board power supply: through USB bus or from an external 5 V supply voltage
External application power supply: 3 V and 5 V
Four LEDs:
- LD1 (red) for 3.3 V power on
- LD2 (red/green) for USB communication
- LD3 (green) for PC9 output
- LD4 (blue) for PC8 output
Two push buttons (user and reset)
Extension header for all LQFP64 I/Os for quick connection to prototyping board and easy probing

More information about STM32L151x can be found in the STM32L1x reference manual [2].

Supported Features

The Zephyr stm32l1_disco and stm32l152c_disco board configurations support the following hardware features:

Supported hardware
Interface	Controller	Driver/component
NVIC	on-chip	nested vector interrupt controller
UART	on-chip	serial port-polling serial port-interrupt
PINMUX	on-chip	pinmux
GPIO	on-chip	gpio
CLOCK	on-chip	reset and clock control
FLASH	on-chip	flash memory
EEPROM	on-chip	eeprom
WATCHDOG	on-chip	window watchdog
I2C	on-chip	i2c
SPI	on-chip	spi

Other hardware features are not yet supported in this Zephyr port.

The configuration of stm32l1_disco can be found in boards/st/stm32l1_disco/stm32l1_disco_defconfig

Configuration of stm32l152c_disco can be found in boards/st/stm32l1_disco/stm32l152c_disco_defconfig

Connections and IOs

Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as input (with or without pull-up or pull-down), or as peripheral alternate function. Most of the GPIO pins are shared with digital or analog alternate functions. All GPIOs are high current capable except for analog inputs.

Default Zephyr Peripheral Mapping:

UART_1_TX : PA9
UART_1_RX : PA10
UART_2_TX : PA2
UART_2_RX : PA3
I2C1_SCL : PB6
I2C1_SDA : PB7
I2C2_SCL : PB10
I2C2_SDA : PB11
SPI1_NSS : PA4
SPI1_SCK : PA5
SPI1_MISO : PA6
SPI1_MOSI : PA7
SPI2_NSS : PB12
SPI2_SCK : PB13
SPI2_MISO : PB14
SPI2_MOSI : PB15

For more details please refer to STM32L1DISCOVERY board User Manual [3].

Programming and Debugging

STM32L1DISCOVERY and STM32L152CDISCOVERY boards include an ST-LINK/V2 embedded debug tool interface.

Applications for the stm32l1_disco board configuration can be built and flashed in the usual way (see Building an Application and Run an Application for more details).

Flashing

The board is configured to be flashed using west STM32CubeProgrammer [4] runner, so its installation is required.

Alternatively, OpenOCD or JLink can also be used to flash the board using the --runner (or -r) option:

$ west flash --runner openocd
$ west flash --runner jlink

Flashing an application

Here is an example for the Blinky application.

# From the root of the zephyr repository
west build -b stm32l1_disco samples/basic/blinky
west flash

You will see the LED blinking every second.

Debugging

You can debug an application in the usual way. Here is an example for the Blinky application.

# From the root of the zephyr repository
west build -b stm32l1_disco samples/basic/blinky
west debug