154 lines
3.5 KiB
Markdown
154 lines
3.5 KiB
Markdown
---
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title: IIC
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updated: 2022-01-11 01:26:41Z
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created: 2022-01-08 13:18:07Z
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---
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# 软件模拟IIC
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```c
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/*
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This sample show how to use MM32 write read EEPROM AT2404 through
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GPIO pin to simulate I2C interface
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下面给出MM32通过GPIO模拟I2C读写EEPROM程序
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*/
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#define I2C1_SCL_PORT GPIOB
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#define I2C1_SCL_PIN GPIO_Pin_13
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#define I2C1_SCL_BUSCLK RCC_AHBPeriph_GPIOB
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#define I2C1_SDA_PORT GPIOB
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#define I2C1_SDA_PIN GPIO_Pin_14
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#define I2C1_SDA_BUSCLK RCC_AHBPeriph_GPIOB
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#define SCL_H I2C1_SCL_PORT->BSRR = I2C1_SCL_PIN
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#define SCL_L I2C1_SCL_PORT->BRR = I2C1_SCL_PIN
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#define SCL_read (I2C1_SCL_PORT-IDR & I2C1_SCL_PIN)
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#define SDA_H I2C1_SDA_PORT->BSRR = I2C1_SDA_PIN
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#define SDA_L I2C1_SDA_PORT->BRR = I2C1_SDA_PIN
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#define SDA_read (I2C1_SDA_PORT->IDR & I2C1_SDA_PIN)
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void I2C_GPIO_Config(void);
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bool EEPROM_ByteWrite(u8 SendByte, u16 WriteAddress, u8 DeviceAddress);
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bool EEPROM_SequentialRead(u8 *pBuffer, u8 length, u16 ReadAddress, u8 DeviceAddress);
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#define I2C_PageSize 16//8
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void delay_ms(__IO uint32_t nTime);
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#define Systick_Delay_1ms delay_ms
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void I2C_GPIO_Config(void)
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{
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GPIO_InitTypeDef GPIO_InitStructure;
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/*Configure I2C1 Pins:SCL and SDA*/
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RCC_AHBPeriphClockCmd(I2C1_SCL_BUSCLK, ENABLE);
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RCC_AHBPeriphClockCmd(I2C1_SDA_BUSCLK, ENABLE);
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GPIO_InitStructure.GPIO_Pin = I2C1_SCL_PIN ;
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GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
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GPIO_Init(I2C1_SCL_PORT, &GPIO_InitStructure);
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GPIO_InitStructure.GPIO_Pin = I2C1_SDA_PIN;
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GPIO_Init(I2C1_SDA_PORT, &GPIO_InitStructure);
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}
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static void I2C_delay(void)
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{
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//set I2C SCL speed 设置通信速度
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u8 i = 13; //100;
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while(i) {
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i--;
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}
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}
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bool I2C_Start(void)
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{
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I2C_delay();
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SDA_H;
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SCL_H;
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I2C_delay();
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if(!SDA_read) return FALSE; //SDA线为低电平总线忙，退出
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SDA_L;
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I2C_delay();
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if(SDA_read) return FALSE; //SDA线为高电平则总线出错，退出
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SDA_L;
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I2C_delay();
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return TRUE;
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}
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void I2C_Stop(void)
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{
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SCL_L;
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I2C_delay();
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SDA_L;
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I2C_delay();
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SCL_H;
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I2C_delay();
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SDA_H;
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I2C_delay();
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}
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void I2C_Ack(void)
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{
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SCL_L;
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I2C_delay();
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SDA_L;
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I2C_delay();
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SCL_H;
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I2C_delay();
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SCL_L;
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I2C_delay();
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}
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void I2C_NoAck(void)
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{
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SCL_L;
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I2C_delay();
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SDA_H;
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I2C_delay();
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SCL_H;
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I2C_delay();
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SCL_L;
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I2C_delay();
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}
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bool I2C_WaitAck(void) //返回为：-1有ACK， =0 无ACK
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{
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bool bstatus;
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SCL_L;
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I2C_delay();
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SDA_H;
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I2C_delay();
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SCL_H;
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I2C_delay();
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if(SDA_read) {
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bstatus = FALSE;
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} else {
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bstatus = TRUE;
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}
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SCL_L;
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return bstatus;
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}
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void I2C_SendByte(u8 SendByte) //数据从高位到低位
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{
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u8 i = 8;
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while(i--) {
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SCL_L;
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I2C_delay();
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if(SendByte & 0x80)
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SDA_H;
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else
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SDA_L;
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SendByte <<= 1;
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I2C_delay();
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SCL_H;
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I2C_delay();
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}
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SCL_L;
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}
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u8 I2C_ReceiveByte(void) //数据从高位到低位
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{
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u8 i = 8;
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u8 ReceiveByte = 0;
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SDA_H;
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while(i--) {
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ReceiveByte <<= 1;
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SCL_L;
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I2C_delay();
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SCL_H;
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I2C_delay();
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if(SDA_read) {
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ReceiveByte |= 0x01;
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}
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}
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SCL_L;
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return ReceiveByte;
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}
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```
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