SPI2_Handler.Init.CLKPolarity = SPI_POLARITY_HIGH;
时间: 2024-06-12 12:05:00 浏览: 150
This line of code sets the clock polarity for SPI2 to be high. In SPI communication, the clock signal synchronizes the data transfer between the master and slave devices. The clock polarity determines the idle state of the clock signal when it is not actively transmitting data. A high polarity means that the clock signal is idle at a high voltage level. The SPI_POLARITY_HIGH is defined as a constant value in the SPI library and is used to set the clock polarity parameter for the SPI initialization structure.
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HAL库初始化SPI2
以下是使用HAL库初始化SPI2的代码示例:
```
SPI_HandleTypeDef hspi2;
void SPI2_Init(void)
{
/* SPI2 parameter configuration */
hspi2.Instance = SPI2;
hspi2.Init.Mode = SPI_MODE_MASTER;
hspi2.Init.Direction = SPI_DIRECTION_2LINES;
hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi2.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi2.Init.NSS = SPI_NSS_SOFT;
hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_256;
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi2) != HAL_OK)
{
Error_Handler();
}
}
```
这个代码示例使用了SPI2作为主设备,并且设置了SPI的各种参数,例如数据传输模式、数据位数、时钟极性、时钟相位等。在最后,使用`HAL_SPI_Init()`函数初始化SPI2,如果初始化失败,会调用`Error_Handler()`函数进行错误处理。
STM32L151 SPI2通道 HAL库初始化
以下是使用HAL库初始化STM32L151的SPI2通道的示例代码:
```c
#include "stm32l1xx_hal.h"
SPI_HandleTypeDef hspi2;
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_SPI2_Init(void);
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_SPI2_Init();
while (1)
{
// 在这里添加你的代码
}
}
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_OSCILLATORTYPE_LSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = 16;
RCC_OscInitStruct.LSIState = RCC_LSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
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_HSI;
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_1) != HAL_OK)
{
Error_Handler();
}
}
static void MX_SPI2_Init(void)
{
hspi2.Instance = SPI2;
hspi2.Init.Mode = SPI_MODE_MASTER;
hspi2.Init.Direction = SPI_DIRECTION_2LINES;
hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi2.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi2.Init.NSS = SPI_NSS_SOFT;
hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 7;
if (HAL_SPI_Init(&hspi2) != HAL_OK)
{
Error_Handler();
}
}
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
__HAL_RCC_GPIOA_CLK_ENABLE();
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
GPIO_InitStruct.Pin = GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF5_SPI2;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}
```
在上面的代码中,我们使用了以下HAL库函数:
- HAL_RCC_OscConfig:用于配置时钟源。
- HAL_RCC_ClockConfig:用于配置系统时钟和外设时钟。
- HAL_SPI_Init:用于初始化SPI2外设。
- HAL_GPIO_Init:用于初始化GPIO外设。
上述代码初始化了SPI2通道所需的GPIO和SPI外设,并配置了SPI的主模式、8位数据传输、时钟极性和相位。你可以根据自己的需要修改这些参数。