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只要能产生I2C时序即可,至于通过什么硬件产生,无所谓,目前有两种方式1. GPIO2. I2C控制器
51单片机上没有i2c控制器,所以在51单片机上只能用gpio来模拟i2c控制器,拉高拉低gpio 来模拟 SCL SDA
GPIO实现了I2C时序,那么这两根线就叫做I2C总线hi3521a 也有用GPIO来模拟I2C的实例
#define I2C_COM_PORT I2C1#define I2C_COM_CLK RCC_APB1Periph_I2C1#define I2C_COM_SCL_PIN GPIO_Pin_8#define I2C_COM_SCL_GPIO_PORT GPIOB#define I2C_COM_SCL_GPIO_CLK RCC_AHB1Periph_GPIOB#define I2C_COM_SCL_SOURCE GPIO_PinSource8#define I2C_COM_SCL_AF GPIO_AF_I2C1#define I2C_COM_SDA_PIN GPIO_Pin_9#define I2C_COM_SDA_GPIO_PORT GPIOB#define I2C_COM_SDA_GPIO_CLK RCC_AHB1Periph_GPIOB#define I2C_COM_SDA_SOURCE GPIO_PinSource9#define I2C_COM_SDA_AF GPIO_AF_I2C1
1. 配置gpio复用 GPIO_InitTypeDef GPIO_InitStructure; RCC_AHB1PeriphClockCmd(I2C_COM_SCL_GPIO_CLK, ENABLE); RCC_AHB1PeriphClockCmd(I2C_COM_SDA_GPIO_CLK, ENABLE); RCC_APB1PeriphClockCmd(I2C_COM_CLK, ENABLE); I2C_Cmd(I2C_COM_PORT, DISABLE); I2C_DeInit(I2C_COM_PORT); /* Configure I2C pins: SCL and SDA ---------------------------------------*/ GPIO_InitStructure.GPIO_Pin = I2C_COM_SCL_PIN | I2C_COM_SDA_PIN; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_OD; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(I2C_COM_SCL_GPIO_PORT, &GPIO_InitStructure); GPIO_PinAFConfig(I2C_COM_SCL_GPIO_PORT, I2C_COM_SCL_SOURCE, I2C_COM_SCL_AF); GPIO_PinAFConfig(I2C_COM_SDA_GPIO_PORT, I2C_COM_SDA_SOURCE, I2C_COM_SDA_AF);2. I2C_InitTypeDef I2C_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; /* I2C configuration -----------------------------------------------------*/ I2C_InitStructure.I2C_Mode = I2C_Mode_I2C; I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2; I2C_InitStructure.I2C_OwnAddress1 = rw_com; I2C_InitStructure.I2C_Ack = I2C_Ack_Enable; I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit; I2C_InitStructure.I2C_ClockSpeed = 100000; I2C_Init(I2C_COM_PORT, &I2C_InitStructure); /* Configure and enable I2Cx event interrupt -------------------------------*/ NVIC_InitStructure.NVIC_IRQChannel = I2C1_EV_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); /* Configure and enable I2C1 error interrupt -------------------------------*/ NVIC_InitStructure.NVIC_IRQChannel = I2C1_ER_IRQn; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; NVIC_Init(&NVIC_InitStructure); /* Enable I2C1 event and buffer interrupts */ I2C_ITConfig(I2C1, I2C_IT_EVT | I2C_IT_BUF, ENABLE); /* Enable I2C1 Error interrupts */ I2C_ITConfig(I2C1, I2C_IT_ERR, ENABLE); // 使能I2C I2C_Cmd(I2C_COM_PORT, ENABLE);3. 发 I2C_SendData(I2C1, I2C_Rx_DATA);4. 收 I2C_ReceiveData
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