uint8_t *rxData;如何赋初始值
时间: 2024-04-21 22:20:25 浏览: 32
uint8_t *rxData是一个指向uint8_t类型的指针变量。要给它赋初始值,可以通过以下几种方式:
1. 直接赋值:可以将一个uint8_t类型的变量的地址赋给rxData,例如:
```
uint8_t data = 10;
rxData = &data;
```
2. 动态分配内存:可以使用malloc函数动态分配内存,并将分配的内存地址赋给rxData,例如:
```
rxData = (uint8_t*)malloc(sizeof(uint8_t));
if(rxData != NULL) {
*rxData = 10;
}
```
3. 数组初始化:如果rxData是一个指向数组的指针,可以通过数组初始化的方式给它赋初值,例如:
```
uint8_t data[] = {1, 2, 3, 4, 5};
rxData = data;
```
请注意,在使用完rxData后,如果使用了动态分配内存的方式,需要使用free函数释放内存,避免内存泄漏。
相关问题
void LPSPI_MasterUserCallback(LPSPI_Type *base, lpspi_master_edma_handle_t *handle, status_t status, void *userData);括号中在应用中如何填写,举个例子
这个函数是LPSPI主机使用EDMA传输时的回调函数。在你的应用中,你需要创建一个lpspi_master_edma_handle_t类型的变量来管理EDMA传输。然后,当你调用LPSPI_MasterTransferEDMA函数时,将这个变量传递给它,以便在传输完成时调用回调函数。在回调函数中,你可以根据status的值来判断传输是否成功,并在userData中传递需要处理的数据。
以下是一个简单的示例:
```
#define LPSPI_MASTER_DMA_CHANNEL (0U)
#define LPSPI_DMA_REQUEST_SOURCE (kDmaRequestMuxLPSPI1Rx)
lpspi_master_config_t masterConfig;
lpspi_master_edma_handle_t masterEdmaHandle;
edma_handle_t dmaHandle;
/* 初始化LPSPI主机配置 */
LPSPI_MasterGetDefaultConfig(&masterConfig);
masterConfig.baudRate_Bps = 500000U;
masterConfig.bitsPerFrame = 8U;
LPSPI_MasterInit(LPSPI1, &masterConfig, CLOCK_GetFreq(kCLOCK_FlexSpi));
/* 设置EDMA传输 */
EDMA_CreateHandle(&dmaHandle, DMA0, LPSPI_MASTER_DMA_CHANNEL);
LPSPI_MasterTransferCreateHandleEDMA(LPSPI1, &masterEdmaHandle, LPSPI_MasterUserCallback, NULL, &dmaHandle, LPSPI_DMA_REQUEST_SOURCE);
/* 发送数据 */
uint8_t txData[10] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A};
LPSPI_MasterTransferEDMA(LPSPI1, &masterEdmaHandle, txData, NULL, 10);
/* 回调函数 */
void LPSPI_MasterUserCallback(LPSPI_Type *base, lpspi_master_edma_handle_t *handle, status_t status, void *userData)
{
if (status == kStatus_Success)
{
/* 处理接收到的数据 */
uint8_t rxData[10];
LPSPI_ReadData(base, rxData, 10);
/* ... */
}
}
```
stm32f103c8t6驱动bmp280
基于STM32F103C8T6驱动BMP280可以使用硬件SPI或者软件I2C进行通信。下面是两种方法的介绍:
1. 使用硬件SPI驱动BMP280:
```c
#include "stm32f10x.h"
#include "spi.h"
#include "bmp280.h"
#define BMP280_CS_PIN GPIO_Pin_4
#define BMP280_CS_PORT GPIOA
void BMP280_SPI_Init(void)
{
// 初始化SPI接口
SPI_InitTypeDef SPI_InitStruct;
SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStruct.SPI_Mode = SPI_Mode_Master;
SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitStruct.SPI_NSS = SPI_NSS_Soft;
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStruct.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStruct);
SPI_Cmd(SPI1, ENABLE);
// 初始化CS引脚
GPIO_InitTypeDef GPIO_InitStruct;
GPIO_InitStruct.GPIO_Pin = BMP280_CS_PIN;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(BMP280_CS_PORT, &GPIO_InitStruct);
}
void BMP280_SPI_CS(uint8_t state)
{
if (state == 0)
{
GPIO_ResetBits(BMP280_CS_PORT, BMP280_CS_PIN);
}
else
{
GPIO_SetBits(BMP280_CS_PORT, BMP280_CS_PIN);
}
}
void BMP280_SPI_Transfer(uint8_t *txData, uint8_t *rxData, uint16_t size)
{
while (size--)
{
SPI_I2S_SendData(SPI1, *txData++);
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET)
;
*rxData++ = SPI_I2S_ReceiveData(SPI1);
}
}
void BMP280_Delay(uint32_t ms)
{
// 延时函数,根据实际情况实现
// 例如使用SysTick定时器
uint32_t start = SysTick->VAL;
uint32_t end = start - ms * (SystemCoreClock / 1000);
if (end > start)
{
while (SysTick->VAL > end)
;
}
else
{
while (SysTick->VAL > end && SysTick->VAL < start)
;
}
}
int main(void)
{
// 初始化SPI和CS引脚
BMP280_SPI_Init();
BMP280_SPI_CS(1);
// 初始化BMP280
bmp280_init(BMP280_SPI_Transfer, BMP280_SPI_CS, BMP280_Delay);
// 获取气压值和温度值
int32_t pressure;
int32_t temperature;
bmp280_get_pressure_temperature(&pressure, &temperature);
// 打印结果
printf("Pressure: %ld Pa\n", pressure);
printf("Temperature: %ld °C\n", temperature);
while (1)
{
}
}
```
2. 使用软件I2C驱动BMP280:
```c
#include "stm32f10x.h"
#include "i2c.h"
#include "bmp280.h"
#define BMP280_I2C_ADDR 0x76
void BMP280_I2C_Init(void)
{
// 初始化I2C接口
I2C_InitTypeDef I2C_InitStruct;
I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
I2C_InitStruct.I2C_OwnAddress1 = 0x00;
I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStruct.I2C_ClockSpeed = 100000;
I2C_Init(I2C1, &I2C_InitStruct);
I2C_Cmd(I2C1, ENABLE);
}
void BMP280_I2C_Write(uint8_t regAddr, uint8_t *data, uint16_t size)
{
I2C_GenerateSTART(I2C1, ENABLE);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT))
;
I2C_Send7bitAddress(I2C1, BMP280_I2C_ADDR, I2C_Direction_Transmitter);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
;
I2C_SendData(I2C1, regAddr);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
;
while (size--)
{
I2C_SendData(I2C1, *data++);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
;
}
I2C_GenerateSTOP(I2C1, ENABLE);
}
void BMP280_I2C_Read(uint8_t regAddr, uint8_t *data, uint16_t size)
{
I2C_GenerateSTART(I2C1, ENABLE);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT))
;
I2C_Send7bitAddress(I2C1, BMP280_I2C_ADDR, I2C_Direction_Transmitter);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
;
I2C_SendData(I2C1, regAddr);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
;
I2C_GenerateSTART(I2C1, ENABLE);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT))
;
I2C_Send7bitAddress(I2C1, BMP280_I2C_ADDR, I2C_Direction_Receiver);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))
;
while (size--)
{
if (size == 0)
{
I2C_AcknowledgeConfig(I2C1, DISABLE);
I2C_GenerateSTOP(I2C1, ENABLE);
}
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED))
;
*data++ = I2C_ReceiveData(I2C1);
}
I2C_AcknowledgeConfig(I2C1, ENABLE);
}
void BMP280_Delay(uint32_t ms)
{
// 延时函数,根据实际情况实现
// 例如使用SysTick定时器
uint32_t start = SysTick->VAL;
uint32_t end = start - ms * (SystemCoreClock / 1000);
if (end > start)
{
while (SysTick->VAL > end)
;
}
else
{
while (SysTick->VAL > end && SysTick->VAL < start)
;
}
}
int main(void)
{
// 初始化I2C接口
BMP280_I2C_Init();
// 初始化BMP280
bmp280_init(BMP280_I2C_Write, BMP280_I2C_Read, BMP280_Delay);
// 获取气压值和温度值
int32_t pressure;
int32_t temperature;
bmp280_get_pressure_temperature(&pressure, &temperature);
// 打印结果
printf("Pressure: %ld Pa\n", pressure);
printf("Temperature: %ld °C\n", temperature);
while (1)
{
}
}
```
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