ST STM32H747I Discovery¶
The discovery kit enables a wide diversity of applications taking benefit from audio, multi-sensor support, graphics, security, video, and high-speed connectivity features.
The board includes an STM32H747XI SoC with a high-performance DSP, Arm Cortex-M7 + Cortex-M4 MCU, with 2MBytes of Flash memory, 1MB RAM, 480 MHz CPU, Art Accelerator, L1 cache, external memory interface, large set of peripherals, SMPS, and MIPI-DSI.
Additionally, the board features:
On-board ST-LINK/V3E supporting USB reenumeration capability
USB ST-LINK functions: virtual COM port, mass storage, debug port
Flexible power-supply options:
ST-LINK USB VBUS, USB OTG HS connector, or external sources
4” capacitive touch LCD display module with MIPI® DSI interface
Ethernet compliant with IEEE802.3-2002
USB OTG HS
Stereo speaker outputs
ST-MEMS digital microphones
4 color user LEDs
1 user and reset push-button
4-direction joystick with selection button
Arduino Uno V3 connectors
More information about the board can be found at the STM32H747I-DISCO website. More information about STM32H747XIH6 can be found here:
The current Zephyr stm32h747i_disco board configuration supports the following hardware features:
nested vector interrupt controller
serial port-polling; serial port-interrupt
Other hardware features are not yet supported on Zephyr porting.
The default configuration per core can be found in the defconfig files:
STM32H747I Discovery kit has 9 GPIO controllers. These controllers are responsible for pin muxing, input/output, pull-up, etc.
For mode details please refer to STM32H747I-DISCO website.
Default Zephyr Peripheral Mapping:¶
UART_1 TX/RX : PA9/PA10 (ST-Link Virtual Port Com)
UART_8 TX/RX : PJ8/PJ9 (Arduino Serial)
LD1 : PI12
LD2 : PI13
LD3 : PI14
LD4 : PI15
W-UP : PC13
J-CENTER : PK2
J-DOWN : PK3
J-LEFT : PK4
J-RIGHT : PK5
J-UP : PK6
The STM32H747I System Clock can be driven by an internal or external oscillator, as well as by the main PLL clock. By default, the CPU1 (Cortex-M7) System clock is driven by the PLL clock at 400MHz, and the CPU2 (Cortex-M4) System clock is driven at 200MHz. PLL clock is feed by a 25MHz high speed external clock.
The STM32H747I Discovery kit has up to 8 UARTs. Default configuration assigns USART1 and UART8 to the CPU1. The Zephyr console output is assigned to UART1 which connected to the onboard ST-LINK/V3.0. Virtual COM port interface. Default communication settings are 115200 8N1.
The dual core nature of STM32H747 SoC requires sharing HW resources between the two cores. This is done in 3 ways:
Compilation: Clock configuration is only accessible to M7 core. M4 core only has access to bus clock activation and deactivation.
Static pre-compilation assignment: Peripherals such as a UART are assigned in devicetree before compilation. The user must ensure peripherals are not assigned to both cores at the same time.
Run time protection: Interrupt-controller and GPIO configurations could be accessed by both cores at run time. Accesses are protected by a hardware semaphore to avoid potential concurrent access issues.
Programming and Debugging¶
Applications for the
stm32h747i_disco board should be built per core target,
`stm32h747i_disco_m4 as the target.
See Building an Application for more information about application builds.
If using OpenOCD you will need a recent development version as the last official release does not support H7 dualcore yet. Also, with OpenOCD, sometimes, flashing is not working. It is necessary to erase the flash (with STM32CubeProgrammer for example) to make it work again. Debugging with OpenOCD is currently working for this board only with Cortex M7, not Cortex M4.
Flashing operation will depend on the target to be flashed and the SoC
option bytes configuration.
It is advised to use STM32CubeProgrammer to check and update option bytes
configuration and flash
CPU1 (Cortex-M7) boot address is set to 0x80000000 (OB: BOOT_CM7_ADD0)
CPU2 (Cortex-M4) boot address is set to 0x81000000 (OB: BOOT_CM4_ADD0)
Also, default out of the box board configuration enables CM7 and CM4 boot when board is powered (Option bytes BCM7 and BCM4 are checked). It is possible to change Option Bytes so that CM7 boots first in stand alone, and CM7 will wakeup CM4 after clock initialization. Drivers are able to take into account both Option Bytes configurations automatically.
Zephyr flash configuration has been set to meet these default settings.
Flashing an application to STM32H747I M7 Core¶
First, connect the STM32H747I Discovery kit to your host computer using the USB port to prepare it for flashing. Then build and flash your application.
Here is an example for the Hello World application.
# From the root of the zephyr repository west build -b stm32h747i_disco_m7 samples/hello_world
Use the following commands to flash either m7 or m4 target:
$ ./STM32_Programmer_CLI -c port=SWD mode=UR -w <path_to_m7_binary> 0x8000000 $ ./STM32_Programmer_CLI -c port=SWD mode=UR -w <path_to_m4_binary> 0x8100000
Alternatively it is possible to flash with OpenOcd but with some restrictions: Sometimes, flashing is not working. It is necessary to erase the flash (with STM32CubeProgrammer for example) to make it work again. Debugging with OpenOCD is currently working for this board only with Cortex M7, not Cortex M4.
# From the root of the zephyr repository west build -b stm32h747i_disco_m7 samples/hello_world west flash
Run a serial host program to connect with your board:
$ minicom -D /dev/ttyACM0
You should see the following message on the console:
Hello World! stm32h747i_disco_m7