I2C_GenerateSTART(I2C_MASTER, ENABLE);
时间: 2024-06-15 22:09:48 浏览: 115
I2C_GenerateSTART(I2C_MASTER, ENABLE)是一个函数,用于在I2C总线上生成起始信号。它的作用是启动一个I2C传输过程,通常用于发送数据之前。
在这个函数中,I2C_MASTER是指要使用的I2C总线,ENABLE是一个参数,表示要生成起始信号。通过调用这个函数,可以向I2C总线发送起始信号,以便开始一个I2C传输过程。
相关问题
I2C_MASTER_SDA_IO
I2C_MASTER_SDA_IO是ESP32芯片的一个GPIO引脚,用于I2C总线的数据线(SDA)。在ESP-IDF中,它被定义为一个宏,它的值为21。如果您正在开发ESP32上的I2C通信应用程序,您需要在引用I2C总线时将其用作SDA引脚的定义。
以下是一个基本的示例代码,展示了如何在ESP32上使用它来配置I2C总线:
```c
#define I2C_MASTER_SDA_IO 21 /*!< GPIO22 -> SDA */
#define I2C_MASTER_SCL_IO 22 /*!< GPIO23 -> SCL */
#define I2C_MASTER_NUM I2C_NUM_0 /*!< I2C port number */
i2c_config_t conf = {
.mode = I2C_MODE_MASTER,
.sda_io_num = I2C_MASTER_SDA_IO,
.sda_pullup_en = GPIO_PULLUP_ENABLE,
.scl_io_num = I2C_MASTER_SCL_IO,
.scl_pullup_en = GPIO_PULLUP_ENABLE,
.master.clk_speed = 100000
};
i2c_param_config(I2C_MASTER_NUM, &conf);
i2c_driver_install(I2C_MASTER_NUM, conf.mode, 0, 0, 0);
```
以上代码示例中,我们定义了I2C总线配置结构体,并将其初始化为主模式,同时将I2C_MASTER_SDA_IO定义为SDA引脚的引脚号。然后,我们通过调用i2c_param_config()函数将配置参数应用于I2C主设备,并安装I2C驱动程序。
#include "i2c.h"#define I2C_SPEED 100000 // I2C总线速度,单位为Hzvoid i2c_init(void){ GPIO_InitTypeDef GPIO_InitStruct; I2C_InitTypeDef I2C_InitStruct; RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); // 使能GPIOB时钟 RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE); // 使能I2C1时钟 // 配置GPIOB6和GPIOB7为复用推挽输出 GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7; GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_OD; GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStruct); // 配置I2C1为标准模式,时钟速度为100kHz 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 = I2C_SPEED; I2C_Init(I2C1, &I2C_InitStruct); I2C_Cmd(I2C1, ENABLE); // 使能I2C1}void i2c_write(uint8_t addr, uint8_t *data, uint16_t len){ uint32_t timeout = 0; while (I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)) { if (++timeout > 0x10000) return; } I2C_GenerateSTART(I2C1, ENABLE); timeout = 0; while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT)) { if (++timeout > 0x10000) return; } I2C_Send7bitAddress(I2C1, addr << 1, I2C_Direction_Transmitter); timeout = 0; while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)) { if (++timeout > 0x10000) return; } while (len--) { I2C_SendData(I2C1, *data++); timeout = 0; while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED)) { if (++timeout > 0x10000) return; } } I2C_GenerateSTOP(I2C1, ENABLE);}void i2c_read(uint8_t addr, uint8_t *data, uint16_t len){ uint32_t timeout = 0; while (I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)) { if (++timeout > 0x10000) return; } I2C_GenerateSTART(I2C1, ENABLE); timeout = 0; while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT)) { if (++timeout > 0x10000) return; } I2C_Send7bitAddress(I2C1, addr << 1, I2C_Direction_Receiver); timeout = 0; while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)) { if (++timeout > 0x10000) return; } while (len--) { if (len == 0) I2C_AcknowledgeConfig(I2C1, DISABLE); timeout = 0; while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED)) { if (++timeout > 0x10000) return; } *data++ = I2C_ReceiveData(I2C1); } I2C_AcknowledgeConfig(I2C1, ENABLE); I2C_GenerateSTOP(I2C1, ENABLE);}
以下是使用STM32 HAL库函数实现的代码示例:
```c
#include "stm32f1xx_hal.h"
#define I2C_SPEED 100000
I2C_HandleTypeDef hi2c1;
void i2c_init(void)
{
hi2c1.Instance = I2C1;
hi2c1.Init.ClockSpeed = I2C_SPEED;
hi2c1.Init.DutyCycle = I2C_DUTYCYCLE_2;
hi2c1.Init.OwnAddress1 = 0x00;
hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c1.Init.OwnAddress2 = 0;
hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
if (HAL_I2C_Init(&hi2c1) != HAL_OK)
{
Error_Handler();
}
}
void i2c_write(uint8_t addr, uint8_t *data, uint16_t len)
{
if (HAL_I2C_Master_Transmit(&hi2c1, addr << 1, data, len, HAL_MAX_DELAY) != HAL_OK)
{
Error_Handler();
}
}
void i2c_read(uint8_t addr, uint8_t *data, uint16_t len)
{
if (HAL_I2C_Master_Receive(&hi2c1, addr << 1, data, len, HAL_MAX_DELAY) != HAL_OK)
{
Error_Handler();
}
}
```
以上代码使用STM32 HAL库函数实现了I2C初始化、写入和读取操作。请注意,需要在CubeMX工具中配置I2C时钟和GPIO引脚。
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