STM32F7, 32-bit timer from 2x 16 bit timers on APB2

[MBo�?.7]

Hi,

I need a faster 32-bit timer (TIM2 and TIM5 which are 32-bits are on 108MHz AHB1). So idea is to chain 2x 16 bit timers on APB2, choose TIM1 and TIM8. But I just can't configure it to work as it should using CubeMX. I'm also not sure how to adjust it so I get what I need: master timer for MSB and slave timer for LSB. I can easly configure each(separate) timer for the period I desire but getting them to work as chained...is another story...

This is the code I have, TIM1 should be used as master, TIM8 as slave:

static void MX_TIM1_Init(void)
{
 
  /* USER CODE BEGIN TIM1_Init 0 */
 
  /* USER CODE END TIM1_Init 0 */
 
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
 
  /* USER CODE BEGIN TIM1_Init 1 */
 
  /* USER CODE END TIM1_Init 1 */
  htim1.Instance = TIM1;
  htim1.Init.Prescaler = 0;
  htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim1.Init.Period = 0xFFFF;
  htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim1.Init.RepetitionCounter = 0;
  htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
  sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_UPDATE;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM1_Init 2 */
 
  /* USER CODE END TIM1_Init 2 */
 
}
 
static void MX_TIM8_Init(void)
{
 
  /* USER CODE BEGIN TIM8_Init 0 */
 
  /* USER CODE END TIM8_Init 0 */
 
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_SlaveConfigTypeDef sSlaveConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
 
  /* USER CODE BEGIN TIM8_Init 1 */
 
  /* USER CODE END TIM8_Init 1 */
  htim8.Instance = TIM8;
  htim8.Init.Prescaler = 0;
  htim8.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim8.Init.Period = 0xFFFF;
  htim8.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim8.Init.RepetitionCounter = 0;
  htim8.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim8) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim8, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sSlaveConfig.SlaveMode = TIM_SLAVEMODE_TRIGGER;
  sSlaveConfig.InputTrigger = TIM_TS_ITR0;
  if (HAL_TIM_SlaveConfigSynchro(&htim8, &sSlaveConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim8, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM8_Init 2 */
 
  /* USER CODE END TIM8_Init 2 */
 
}
 

After that I start TIM8 and then TIM1.

if (HAL_TIM_Base_Start(&htim8) != HAL_OK)
  {
	  Error_Handler();
  }
 
  if (HAL_TIM_Base_Start(&htim1) != HAL_OK)
  {
	  Error_Handler();
  }

I get individual counters and calculate the value as this:

uint32_t counter1 = __HAL_TIM_GET_COUNTER(&htim1);
uint32_t counter8 = __HAL_TIM_GET_COUNTER(&htim8);
uint32_t combined = ((counter1 * 0xFFFF) + counter8);
printf("T: %5lu | %5lu | %lu\r\n", counter1, counter8, combined);

But counter1 and counter8 have similar values. So I guess I'm triggering the slave wrongly...

What the heck is wrong? TIM8 trigger source? TIM8 slave mode?

Thnx!

[MBo�?.7]

Using CPLD/FPGA or TDC7200 would require a lot of different code.

Managed to get zero jitter at the external interrupt. We are still testing with different scenarios.

Anyways, still didn't get an answer to question: "How to use 2x 16 bit timers on APB2 as 32 bit timer". :)

[MBo�?.7]

Damn...

Jitter free is a no go.

The line which does math introduces a lot of jitter! :(

And no way to make jitter constant as we can compensate something which is constant.

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define RECORDS  100
uint32_t records[RECORDS];
uint32_t current = 0;
uint32_t last = 0;
uint32_t diff = 0;
uint32_t recordsIndex = 0;
/* USER CODE END PD */
 
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
 
/* USER CODE END PM */
 
/* Private variables ---------------------------------------------------------*/
 
CRC_HandleTypeDef hcrc;
 
I2C_HandleTypeDef hi2c2;
 
SPI_HandleTypeDef hspi1;
 
TIM_HandleTypeDef htim5;
TIM_HandleTypeDef htim13;
TIM_HandleTypeDef htim14;
 
UART_HandleTypeDef huart3;
 
/* USER CODE BEGIN PV */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
	if (htim == &htim13)
	{
		HAL_GPIO_TogglePin(LD2_GPIO_Port, LD2_Pin);
	}
	else if (htim == &htim14)
	{
		HAL_GPIO_TogglePin(LD3_GPIO_Port, LD3_Pin);
	}
}
 
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART3_UART_Init(void);
static void MX_CRC_Init(void);
static void MX_SPI1_Init(void);
static void MX_I2C2_Init(void);
static void MX_TIM13_Init(void);
static void MX_TIM14_Init(void);
static void MX_TIM5_Init(void);
void MX_USB_HOST_Process(void);
 
/* USER CODE BEGIN PFP */
int _write(int file, char *ptr, int len)
{
	HAL_UART_Transmit(&huart3, (uint8_t*)ptr, len, (10*len));
	return len;
}
/* USER CODE END PFP */
 
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
uint32_t difference(const uint32_t current, const uint32_t last)
{
	if (current > last)
	{
		return (current - last);
	}
	return (0xFFFFFFFF - current) + last;
}
 
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
	current = __HAL_TIM_GET_COUNTER(&htim5);
	diff = difference(current, last);
	if (recordsIndex < RECORDS)
	{
		records[recordsIndex++] = diff;
	}
	last = current;
}
 
/* USER CODE END 0 */
 
/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */
 
  /* USER CODE END 1 */
 
  /* Enable I-Cache---------------------------------------------------------*/
  SCB_EnableICache();
 
  /* Enable D-Cache---------------------------------------------------------*/
  SCB_EnableDCache();
 
  /* MCU Configuration--------------------------------------------------------*/
 
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* USER CODE BEGIN Init */
 
  /* USER CODE END Init */
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* USER CODE BEGIN SysInit */
 
  /* USER CODE END SysInit */
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART3_UART_Init();
  MX_USB_HOST_Init();
  MX_FATFS_Init();
  MX_CRC_Init();
  MX_SPI1_Init();
  MX_I2C2_Init();
  MX_TIM13_Init();
  MX_TIM14_Init();
  MX_TIM5_Init();
  /* USER CODE BEGIN 2 */
  usb.connected = 0;
  FD_Initialize(&hspi1);
  EEPROM_Initialize(&hi2c2);
  CRC_Initialize(&hcrc);
  printf("App Start...\r\n");
  HAL_GPIO_WritePin(LD1_GPIO_Port, LD1_Pin, GPIO_PIN_SET);
 
  HAL_TIM_Base_Start_IT(&htim5);
  HAL_TIM_Base_Start_IT(&htim13);
  HAL_TIM_Base_Start_IT(&htim14);
 
  uint32_t idx = 0;
  uint64_t value = 0;
 
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
 
	if (recordsIndex >= RECORDS)
	{
		for (i = 0; i < RECORDS; i++)
		{
			printf("D: %lu\r\n", records[i]);
		}
		recordsIndex = 0;
	}
 
	// Line below introduces a lot of jitter which we can not have !!!
	value = idx++ * value;
 
    /* USER CODE END WHILE */
    //MX_USB_HOST_Process();
 
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}