How to generate exact 1us interrupt on STM32f7xx using Hardware Timers - c

I am new to interrupt-based programming.
In my current project, I need the interrupt generated exactly at 1us interval.
Below is the screenshot from the Clock Configuration tab in CubeMX.
I am using the TIM3 timer as it can generate the clock frequency of 1us.
Below is the TIM3 configuration code.
static void MX_TIM3_Init(void)
{
TIM_ClockConfigTypeDef sClockSourceConfig;
TIM_MasterConfigTypeDef sMasterConfig;
htim3.Instance = TIM3;
htim3.Init.Prescaler = 1-1 ;//0x00;// 0x36; || 0x00//1-1
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 0xffff-1; //0x64; || 0xd7 //0xffff-1
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
I am calling the timer
HAL_TIM_IRQHandler(&htim3);
/* USER CODE BEGIN TIM3_IRQn 1 */
HAL_GPIO_TogglePin(GPIOB,GPIO_PIN_6);
I see that the interrupt of duration 1.2ms is generated.
Can anyone let me why is this happening and how can I reduce the interrupt to 1us duration?
Any change required in the timer frequency?
I am also using freeRTOS and other applications are also running on the microcontroller.
Any help in this is highly appreciated.
Thanks in Advance

If your requirement output an accurate 500KHz 1:1 mark/space signal (i.e. 1us high, 1us low), then doing that through interrupts while expecting your system to do other useful work is both impractical an unnecessary. The general purpose timers have a output-compare function that can drive a GPIO pin directly without interrupts or software overhead.
Only certain pins are connected to the Timer OC channels, so to drive PB6 in this case you would need to use TIM4 Channel 1.
Also rather than determining and hard-coding timer reload and pulse, you should use the available HAL RCC clock functions (HAL_RCC_GetPCLK1Freq() in this case) to calculate the values to avoid erros, and so that the code will be portable to other systems or will work correctly if you change your clock configuration.
static void MX_TIM4_Init(void)
{
cost uint32_t PULSE_WIDTH = HAL_RCC_GetPCLK1Freq() * 2 / 1000000 ;
htim4.Instance = TIM4 ;
htim4.Init.Prescaler = 0;
htim4.Init.CounterMode = TIM_COUNTERMODE_UP ;
htim4.Init.Period = PULSE_WIDTH * 2 ;
htim4.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1 ;
HAL_TIM_PWM_Init( &htim4 ) ;
TIM_MasterConfigTypeDef sMasterConfig ;
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig);
TIM_OC_InitTypeDef sConfigOC ;
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = PULSE_WIDTH ;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
HAL_TIM_PWM_ConfigChannel(&htim4, &sConfigOC, TIM_CHANNEL_1);
}
Then elsewhere you need to configure PB6 as an output and start the timer:
LL_GPIO_InitTypeDef GPIO_InitStruct = {0} ;
GPIO_InitStruct.Pin = GPIO_PIN_6 ;
GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE ;
GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_LOW ;
GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL ;
GPIO_InitStruct.Pull = LL_GPIO_PULL_NO ;
GPIO_InitStruct.Alternate = LL_GPIO_AF_2 ;
LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOB)
LL_GPIO_Init(GPIOB, &GPIO_InitStruct);
HAL_TIM_PWM_Start( &htim4, TIM_CHANNEL_1 ) ;
Thereafter the signal will be maintained indefinitely on PB6 with no GPIO access or interrupt handling.

Related

Unable to receive timer interrupt

I am using STM32L496RG board where I'm trying to generate a timer interrupt. But my code does not enter the TIM3_IRQHandler function at all. Initially, I thought my timer settings are wrong, so I created a test code using CUBEMX software to generate a timer interrupt, where it worked. I copied the settings from the test code to my code, but it still does not seem to work on my code. My timer initialisation -
/**
* #brief TIM3 Initialization Function
* #param None
* #retval None
*/
void MX_TIM3_Init()
{
TIM_ClockConfigTypeDef sClockSourceConfig;
TIM_MasterConfigTypeDef sMasterConfig;
htim3.Instance = TIM3;
htim3.Init.Prescaler = 0;
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 0;
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
{
while(1);
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
{
while(1);
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
{
while(1);
}
}
I have started the timer using HAL_TIM_BASE_START_IT(&htim3).I was also doubtful of my clock settings, so I have even copied the clock settings from my test program,but it still did not work. Clock settings -
void SystemClock_Config()
{
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_ClkInitTypeDef RCC_ClkInitStruct;
/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
RCC_OscInitStruct.MSIState = RCC_MSI_ON;
RCC_OscInitStruct.MSICalibrationValue = 0;
RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
RCC_OscInitStruct.PLL.PLLN = 40;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
while(1);
}
/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)
{
while(1);
}
/**Configure the main internal regulator output voltage
*/
if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK)
{
while(1);
}
/**Configure the Systick interrupt time
*/
HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
/**Configure the Systick
*/
HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
/* SysTick_IRQn interrupt configuration */
HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}
Need some help to figure out what's happening.

Issue with frequency limitation on the Timers on STM32F7

I'm having issues setting the timers on the STM32F7 dissovery board to 500 Khz. I seem to top around around 370kHz for some reason. 'm toggling a GPIO pin with a scope to the input and simply changing the Period on the timer to monitor what's happening.
I'm using CubeMX to generate my project files and I initialise my timer:
static void MX_TIM1_Init(void)
{
TIM_ClockConfigTypeDef sClockSourceConfig = {0};
TIM_MasterConfigTypeDef sMasterConfig = {0};
htim1.Instance = TIM1;
htim1.Init.Prescaler = 0;
htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
htim1.Init.Period = 108;
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_OC1;
sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_OC1REF;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
}
I then start the timer in interrupt mode:
if(HAL_TIM_Base_Start_IT(&htim1) != HAL_OK)
{
Error_Handler();
}
and then toggle a GPIO pin when the period has elapsed:
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
if(htim->Instance == TIM1)
{
HAL_GPIO_TogglePin(GPIOG, GPIO_PIN_6);
}
}
The GPIO pin is set as:
GPIO_InitStruct.Pin = GPIO_PIN_6;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);
However, I've played around with the Period on the timer and I've gotten the following results:
539 = 100KHz
239 = 300KHz
215 = 330KHz
108 = 369Khz
I'd expect to get 500Khz with a Period of 215 but this isn't the case.Is there anything wrong with my settings?
The timer settings are right. The interrupt code is too slow.
The HAL library is not suited for timing critical applications. HAL tries (and fails) to handle every possible use case in one-size-fits-all functions, which means lots of unnecessary processing with associated delays. Use a simple interrupt handler instead of the TIM1_IRQHandler() supplied by HAL that just clears the interrupt status and inverts a bit directly in GPIOG->ODR. This should do:
void TIM1_IRQHandler(void) {
TIM1->SR = ~TIM_SR_UIF;
GPIOG->ODR ^= (1 << 6);
}
just 2 lines of code, instead of the 100+ lines of HAL_TIM_IRQHandler(). Should work up to 1 MHz, maybe more.
Toggling output pins in a timer interrupt handler is fine as an embedded programming exercise, but it wastes a significant amount of CPU cycles to achieve what a timer can do alone, delaying and possibly blocking other tasks.
A timer can output a square wave (PWM signal) on its output channels with frequencies up to the half of its source clock. Look for PWM edge-aligned mode in the Reference Manual.

DMA callback return the same value every loop

I am currently working with a STM32f407G-DISC1 and trying to catch a buffer with the ADC and the DMA callback.
A Frequency generator is connected to the pin A0 and the board is grounded.
I verified that my wires weren't broken with an oscilloscope.
Now the problem is that after setting up my project and compiling it the DMA callback is called every time my buffer is filled. My problem is that the buffer is filled with the same values each call.
I've done exactly the same project on a STM32F401RE board. The code is approximately the same except the code generated with CUBEMX.
At first I though I was making a mistake in CUBEMX so I tried to generate another project using another ADC on the board. But I got exactly the same result.
Also, I tried to use another board (I have two of them); Same result.
ADC_HandleTypeDef hadc1;
volatile uint32_t ADCValue1[1];
void main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_DMA_Init();
MX_ADC1_Init();
HAL_ADC_Start_DMA(&hadc1, (uint32_t *) ADCValue1, 1);
while (1) {}
return;
}
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Configure the main internal regulator output voltage
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLM = 8;
RCC_OscInitStruct.PLL.PLLN = 84;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 4;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
}
static void MX_ADC1_Init(void)
{
ADC_ChannelConfTypeDef sConfig = {0};
/** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
*/
hadc1.Instance = ADC1;
hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
hadc1.Init.Resolution = ADC_RESOLUTION_12B;
hadc1.Init.ScanConvMode = DISABLE;
hadc1.Init.ContinuousConvMode = ENABLE;
hadc1.Init.DiscontinuousConvMode = DISABLE;
hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
hadc1.Init.NbrOfConversion = 1;
hadc1.Init.DMAContinuousRequests = ENABLE;
hadc1.Init.EOCSelection = ADC_EOC_SEQ_CONV;
if (HAL_ADC_Init(&hadc1) != HAL_OK)
{
Error_Handler();
}
/** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
*/
sConfig.Channel = ADC_CHANNEL_0;
sConfig.Rank = 1;
sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
{
Error_Handler();
}
}
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA2_CLK_ENABLE();
/* DMA interrupt init */
/* DMA2_Stream0_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA2_Stream0_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA2_Stream0_IRQn);
}
static void MX_GPIO_Init(void)
{
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
}
/* This is the callback called each time my buffer is filled */
void DMA2_Stream0_IRQHandler(void)
{
if ((DMA2->LISR & DMA_LISR_TCIF0) && (DMA2_Stream0->CR & DMA_SxCR_TCIE))
DMA2->LIFCR = DMA_LIFCR_CTCIF0; // acknowledge interrupt
DMA_IRQHandler(); // The function where I want to process my buffer
return;
/* transmission complete interrupt */
}
void DMA_IRQHandler(void)
{
return;
}
Each time I enter the callback my buffer is filled with the exact same values instead of different values.
If you have any ideas...
If you need more code just ask and I'll provide it.
If the code that you didn't bother to post is working correctly, then the buffer would contain the most recent DMA readings every time the interrupt handler is called.
But the compiler has no way of knowing that the buffer is modified by the DMA hardware, because it's not declared as volatile.
There are two obvious problems:
DMA buffers must always be declared volatile or the compiler might do strange optimizations when it realizes that no software updates the variable. Why ST's bloatware doesn't take a volatile qualified parameter is an excellent question to ST - probably yet another bug in their libs.
The function declaration is
HAL_ADC_Start_DMA (ADC_HandleTypeDef *hadc, uint32_t *pData, uint32_t Length)
Meaning you must naturally pass a uint32_t * and not something else. Instead you pass a unsigned short* which you brute force convert to uint32_t*. This gives 2 bugs: the callback might write out of bounds and/or misaligned to your 16 bit variable. And it is also a strict aliasing violation.

Configuring ADC with DMA on Nucleo-F401RE gives erratic values

I want to configure ADC with DMA on STM32(Nucleo-F401RE) and transmit the values through SPI to Basys 3 FPGA. Before transmission through SPI, when i read the values in memory realtime using STMSTudio, it is erratic.
In the past,I have tried increasing the sampling cycles, the issue persists.
Configured ADC without DMA with HAL_ADC_Start function and transferred the values to PC through UART, unable to retrieve the original signal. I'm unable to isolate where the problem lies.
uint32_t ADC1ConvertedValues[100];
int main(void) {
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_DMA_Init();
MX_ADC1_Init();
MX_SPI1_Init();
while (1) {
HAL_GPIO_WritePin(GPIOA,GPIO_PIN_9,GPIO_PIN_SET);
if (HAL_ADC_Start_DMA(&hadc1, (uint32_t*)ADC1ConvertedValues, 100) == HAL_OK) {
HAL_GPIO_WritePin(GPIOA,GPIO_PIN_9,GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1,(uint8_t*)(ADC1ConvertedValues),4,1);
HAL_GPIO_WritePin(GPIOA,GPIO_PIN_9,GPIO_PIN_SET);
}
}
}
void SystemClock_Config(void) {
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLM = 16;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
RCC_OscInitStruct.PLL.PLLQ = 7;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
Error_Handler();
}
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) {
Error_Handler();
}
}
static void MX_ADC1_Init(void) {
ADC_ChannelConfTypeDef sConfig = {0};
hadc1.Instance = ADC1;
hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
hadc1.Init.Resolution = ADC_RESOLUTION_8B;
hadc1.Init.ScanConvMode = ENABLE;
hadc1.Init.ContinuousConvMode = ENABLE;
hadc1.Init.DiscontinuousConvMode = DISABLE;
hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
hadc1.Init.NbrOfConversion = 1;
hadc1.Init.DMAContinuousRequests = ENABLE;
hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
if (HAL_ADC_Init(&hadc1) != HAL_OK) {
Error_Handler();
}
sConfig.Channel = ADC_CHANNEL_0;
sConfig.Rank = 1;
sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) {
Error_Handler();
}
}
static void MX_SPI1_Init(void) {
/* SPI1 parameter configuration*/
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi1) != HAL_OK) {
Error_Handler();
}
}
static void MX_DMA_Init(void) {
__HAL_RCC_DMA2_CLK_ENABLE();
HAL_NVIC_SetPriority(DMA2_Stream0_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA2_Stream0_IRQn);
}
static void MX_GPIO_Init(void) {
GPIO_InitTypeDef GPIO_InitStruct = {0};
__HAL_RCC_GPIOA_CLK_ENABLE();
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_9, GPIO_PIN_RESET);
GPIO_InitStruct.Pin = GPIO_PIN_9;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}
void Error_Handler(void) {
}
#ifdef USE_FULL_ASSERT
void assert_failed(uint8_t *file, uint32_t line) {
#endif /* USE_FULL_ASSERT */
EDIT 1: I used the arduino IDE to program NUCLEO-f401 RE and below is the code used :
#include <f401reMap.h>
float analogPin = pinMap(31); //PA0
float val = 0; // variable to store the value read
void setup() {
Serial.begin(115200); // setup serial
analogReadResolution(12);
}
void loop() {
val = analogRead(analogPin); // read the input pin
Serial.println(val); // debug value
}
It works for input signal frequency below 100Hz. How do I increase the throughput rate? My project requires conversion of analog signal between 500KHz to 900Khz.
Tried changing the DMA buffer size/speed uint32_t ADC1ConvertedValues[100]; reading about the DMA for this chip for my project I found that this sets the size of memory direct memory access allocated samples per clock? If it was I2C or if you would like to read about the timing concepts keep reading You need to find the ADC registers that set the spi baud rate and account for the setup requirements or re-initialization.
hadc1.Instance = ADC1;// this selects analog to digital circuit one
hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4; //"skip" 3 out of 4 clock steps in sync with time scale read on...
hadc1.Init.Resolution = ADC_RESOLUTION_8B; //use 8 bits to pack the numbers to send to the intergrated CPU of the f401
Background on the math
ADC and DMA are often classifyed in read rate at the spi level not at the analog level. So if the chip can do 8khz spi using 8 bits then we can calculate in bigO (8n+n) time that we should get just under 1khz read speed. HOWEVER you need to write 8 bits to receive 8bits so bigO time is now bigO(n16+n) . But because of continuous register I believe it could be as low as bigO (8n+n+8) or (8n+n+8setupbits). So using that we know the time consumed by the intermediate operations in terms of clock cycles note that the term n alone is to account for assumptions of unknown internal clock trigger conditions and should have a scalar that relative to theta if scale resolution is a absolute requirement. Also keep in mind that these frequencies you may be experiencing noise from impedance resistance and capacitance.

Is a TIM interrupt also blocking background counting on STM32?

As the title says, with an STM32 if an interrupt lasts for 1 microsecond should one compensate the CCR by 1 microsecond converted in counter cycles in order to achieve the correct duty cycle?
For example with a period of 100Khz and an overflow interrupt of 1 microsecond should i use a CCR = 50Khz to achieve duty cycle of 50% or should i use a CCR = 50kHz - interrupt delay? Keep in mind that i'm using shadow register to preload the next period/duty cycle combination dynamically.
Oscilloscope readings tells me the second.
Does a flag for automatic compensation exist?
Below some code snippets
void MX_TIM9_Init(void){
TIM_OC_InitTypeDef sConfigOC;
htim9.Instance = TIM9;
htim9.Init.Prescaler = PSC; // Get clock to <freq> Hz
htim9.Init.CounterMode = TIM_COUNTERMODE_UP;
htim9.Init.Period = 250;
htim9.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
HAL_TIM_PWM_Init(&htim9);
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = 125;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_ENABLE;
sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
HAL_TIM_PWM_ConfigChannel(&htim9, &sConfigOC, TIM_CHANNEL_1);
__HAL_TIM_ENABLE_IT(&htim9, TIM_IT_UPDATE);
TIM9->CR1 |= TIM_CR1_ARPE;
}
void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef* htim_pwm){
GPIO_InitTypeDef GPIO_InitStruct;
if(htim_pwm->Instance==TIM9){
__TIM9_CLK_ENABLE();
/* Peripheral interrupt init*/
HAL_NVIC_SetPriority(TIM1_BRK_TIM9_IRQn, 1, 1);
HAL_NVIC_EnableIRQ(TIM1_BRK_TIM9_IRQn);
GPIO_InitStruct.Pin = GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_LOW;
GPIO_InitStruct.Alternate = GPIO_AF3_TIM9;
HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
}
}
void TIM1_BRK_TIM9_IRQHandler(void){
if(__HAL_TIM_GET_FLAG(&htim9, TIM_FLAG_UPDATE) != RESET){
if(__HAL_TIM_GET_IT_SOURCE(&htim9, TIM_IT_UPDATE) !=RESET){
__HAL_TIM_CLEAR_IT(&htim9, TIM_IT_UPDATE);
myFunction(void);
}
}
}
void myFunction(){
//perform logics with if
tim9->ARR = r; // r is a value coming from the logics above
tim9->CCR1 = r / 2;
}
No - interrupts have not anything with the timers. When the interrupt line is set by the timer, it counts as normally - and the interrupt is dealt by the interrupt controller & the core. You do not have to compensate anything.

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