{"id":4221,"date":"2020-10-28T20:00:29","date_gmt":"2020-10-28T19:00:29","guid":{"rendered":"https:\/\/msalamon.pl\/?p=4221"},"modified":"2025-12-27T16:11:37","modified_gmt":"2025-12-27T15:11:37","slug":"running-code-on-two-cores-of-the-stm32h745","status":"publish","type":"post","link":"https:\/\/msalamon.pl\/en\/running-code-on-two-cores-of-the-stm32h745\/","title":{"rendered":"Running code on two cores of the STM32H745"},"content":{"rendered":"\n

In the previous post<\/a> in the dual-core series, I showed you a really strong contender, namely the STM32H745<\/a>, which is on the Nucleo<\/a> 144-size board. I got to the point where I created the first project. We already have the project structure behind us. So how do we run our code now?<\/p>\n\n\n\n\n\n\n

\n
\"\"<\/a><\/figure>\n<\/div>\n\n\n

<\/p>\n\n\n\n

The \u201cmain\u201d core \u2013 MCU start<\/h1>\n\n\n\n

Who rules in the STM32H745<\/a> package? It seems like the stronger one, i.e., Cortex-M7. You might think that Cortex-M7 in such a case will initialize the whole microcontroller. And that is exactly the default behavior.<\/p>\n\n\n\n

Cube generates the project in Boot Mode Sequence 1. What is this sequence about? I summarized the whole thing in a table.<\/p>\n\n\n\n

Cortex-M4<\/strong><\/td>Cortex-M7<\/strong><\/td><\/tr>
Start<\/td>Start<\/td><\/tr>
Enables semaphores and activates notifications on HSEM_ID_0<\/td>Waits until Cortex-M4 enters STOP Mode<\/td><\/tr>
Clears Events and enters STOP Mode<\/td><\/td><\/tr>
<\/td>Initializes HAL<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
<\/td>Configures clocks (shared for both cores)<\/td><\/tr>
<\/td>Takes semaphore HSEM_ID_0<\/td><\/tr>
<\/td>Releases semaphore HSEM_ID_0 (sending a notification to Cortex-M4 to wake it up)<\/td><\/tr>
<\/td>Waits for Cortex-M4 to wake up<\/td><\/tr>
Wakes up after the semaphore notification<\/td><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Initializes HAL<\/td>Initializes its peripherals<\/td><\/tr>
Initializes its peripherals<\/td>Runs<\/td><\/tr>
Runs<\/td><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

<\/p>\n\n\n\n

After this startup sequence, both cores are already working. Each according to its own program, because after all we write two separate programs, if you remember from the previous post<\/a>.<\/p>\n\n\n\n

A simple LED blinking program<\/h2>\n\n\n\n

What\u2019s the first thing you can do on a microcontroller that\u2019s new to you? Of course\u2014blink an LED! On the NUCLEO-H745ZI-Q<\/a> we have as many as three LEDs compared to the smaller Nucleo<\/a>. Green, yellow, and red.<\/p>\n\n\n

\n
\"\"<\/a><\/figure>\n<\/div>\n\n\n

On one core we\u2019ll blink the green one, on the other the red one. We\u2019ll do both blinks using HAL_Delay, so we\u2019ll finally be able to run \u201ctwo things at once\u201d \ud83d\ude09<\/p>\n\n\n\n

The code is trivially simple. In main.c for Cortex-M4, in the main loop you just blink the LED.<\/p>\n\n\n\n

  \/* Infinite loop *\/\n  \/* USER CODE BEGIN WHILE *\/\n  while (1)\n  {\n\t  HAL_GPIO_TogglePin(LD1_GPIO_Port, LD1_Pin);\n\t  HAL_Delay(500);\n    \/* USER CODE END WHILE *\/\n\n    \/* USER CODE BEGIN 3 *\/\n  }\n  \/* USER CODE END 3 *\/<\/pre>\n\n\n\n
On the second core, Cortex-M7, we write in a different main.c, but the code will look almost the same. It differs in the LED number and the blink speed.<\/p>\n\n\n\n
  \/* Infinite loop *\/\n  \/* USER CODE BEGIN WHILE *\/\n  while (1)\n  {\n\t  HAL_GPIO_TogglePin(LD3_GPIO_Port, LD3_Pin);\n\t  HAL_Delay(300);\n    \/* USER CODE END WHILE *\/\n\n    \/* USER CODE BEGIN 3 *\/\n  }\n  \/* USER CODE END 3 *\/<\/pre>\n\n\n\n
That\u2019s it for the code. The real difficulties start only now\u2014now that we want to run it on the microcontroller as a debug session, to inspect the operation of the whole system.<\/p>\n\n\n\n
Starting Debug on the STM32H745<\/h2>\n\n\n\n
You can find the entire startup sequence in the appropriate ST document<\/a>. It contains information on how to get started with dual-core<\/a> in STM32CubeIDE. Let me present you the most important part, namely how to start debugging.<\/p>\n\n\n\n
In short:<\/p>\n\n\n\n