STM32--模拟I2C.doc

STM32-模拟I2C_2402-SDA_H,SDA_L标签：cdelayconstantsvariablesapplicationfile2011-01-02 10:105564人阅读评论(0)收藏举报分类：STM32（9）=I2C的引脚配置：/* Configure I2C1 pins: SCL and SDA */ GPIO_InitStructure.GPIO_Pin =GPIO_Pin_6 | GPIO_Pin_7;/?QUS1:STM32内部结构 GPIO_InitStructure.GPIO_Speed =GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode =GPIO_Mode_Out_OD; /?QUS2:种模式的区别 GPIO_Init(GPIOB, &GPIO_InitStructure);=/* File Name : i2c_fram.h* Author : MCD Application Team* Version : V2.0.1* Date : 06/13/2008* Description : Header for i2c_ee.c module*/* Define to prevent recursive inclusion - */#ifndef _I2C_FRAM_H#define _I2C_FRAM_H/* Includes -*/#include stm32f10x_lib.h/* Exported types -*/* Exported constants -*/* Exported macro -*/* Exported functions - */*主函数的调用格式，重点。1主机存放数据的地址，2.2402写入地址，3. 写入个数如：#definepr (u8*)0x2000f32c) (pr,0,1)*/bool I2C_FRAM_BufferWrite(u8* pBuffer, u16 WriteAddr, u16 NumByteToWrite);bool I2C_FRAM_BufferRead(u8* pBuffer, u16 ReadAddr, u16 NumByteToRead);#endif /* _I2C_FRAM_H */=/* File Name : i2c_fram.c* Author : Appcat* Version : V0.0.1* Date : 07/11/2009* Description : This file provides a set of functions needed to manage the* communication between I2C peripheral and I2C FM24CL16 FRAM.*/* Includes -*/#include i2c_fram.h/* Private typedef -*/* Private define -*/#define I2C_Speed 100000#define I2C1_SLAVE_ADDRESS7 0xA0#define I2C_PageSize 256 /一页的大小，此处设置一个芯片为一页#define SCL_H GPIOB-BSRR = GPIO_Pin_6 /STM32的两个很specil的寄存器，可很方便的实现GPIO的置1/置0的动作。#define SCL_L GPIOB-BRR = GPIO_Pin_6/ QUS3:进一步了解这两个寄存器，区别于ODR/IDR ,初始化#define SDA_H GPIOB-BSRR = GPIO_Pin_7#define SDA_L GPIOB-BRR = GPIO_Pin_7#define SCL_read GPIOB-IDR & GPIO_Pin_6#define SDA_read GPIOB-IDR & GPIO_Pin_7/* Private macro -*/* Private variables -*/vu8 FRAM_ADDRESS;/* Private function prototypes -*/*/void I2C_delay(void) u8 i=150; /这里可以优化速度 ，经测试最低到5还能写入 while(i) i-; bool I2C_Start(void)/QUS4:STM32中的bool 类型是不是和51中的sbit是一个类型SDA_H;SCL_H;I2C_delay();if(!SDA_read)return FALSE; /SDA线为低电平则总线忙,退出SDA_L;I2C_delay();if(SDA_read) return FALSE; /SDA线为高电平则总线出错,退出SDA_L;I2C_delay();return TRUE;void I2C_Stop(void)SCL_L;I2C_delay();SDA_L;I2C_delay();SCL_H;I2C_delay();SDA_H;I2C_delay();void I2C_Ack(void)SCL_L;I2C_delay();SDA_L;I2C_delay();SCL_H;I2C_delay();SCL_L;I2C_delay();void I2C_NoAck(void)SCL_L;I2C_delay();SDA_H;I2C_delay();SCL_H;I2C_delay();SCL_L;I2C_delay();bool I2C_WaitAck(void) /返回为:=1有ACK,=0无ACKSCL_L;I2C_delay();SDA_H;I2C_delay();SCL_H;I2C_delay();if(SDA_read) SCL_L; return FALSE;SCL_L;return TRUE;void I2C_SendByte(u8 SendByte) /数据从高位到低位/ u8 i=8; while(i-) SCL_L; I2C_delay(); if(SendByte&0x80) SDA_H; else SDA_L; SendByte=1; I2C_delay();SCL_H; I2C_delay(); SCL_L;u8 I2C_ReceiveByte(void) /数据从高位到低位/ u8 i=8; u8 ReceiveByte=0; SDA_H; while(i-) ReceiveByte=1; SCL_L; I2C_delay(); SCL_H; I2C_delay(); if(SDA_read) ReceiveByte|=0x01; SCL_L; return ReceiveByte;bool I2C_FRAM_BufferWrite(u8* pBuffer, u16 WriteAddr, u16 NumByteToWrite)u8 Addr = 0, count = 0;Addr = WriteAddr / I2C_PageSize;/I2C_PageSize可在宏定义中更改页面大小。count = WriteAddr % I2C_PageSize;/用除余将其分页，理解。Addr = Addr 1;Addr = Addr & 0x0F;FRAM_ADDRESS = I2C1_SLAVE_ADDRESS7 | Addr; if (!I2C_Start() return FALSE;I2C_SendByte(FRAM_ADDRESS);/设置器件地址+段地址/1.第一次发送字节，被认为是器件地址(A0A1A2),以及段地址（页/片地址） if (!I2C_WaitAck()I2C_Stop();return FALSE;I2C_SendByte(count); /设置段内地址/2第二次发送字节，被认为是被选中的片的内部地址I2C_WaitAck();while(NumByteToWrite-)I2C_SendByte(* pBuffer); /3第三次发送就可以是写入/读取的内容的。 I2C_WaitAck(); pBuffer+;I2C_Stop();/注意：因为这里要等待EEPROM写完，可以采用查询或延时方式(10ms) /Systick_Delay_1ms(10);return TRUE;/读出1串数据bool I2C_FRAM_BufferRead(u8* pBuffer, u16 WriteAddr, u16 NumByteToRead)u8 Addr = 0, count = 0; Addr = WriteAddr / I2C_PageSize;count = WriteAddr % I2C_PageSize;Addr = Addr 1;Addr = Addr & 0x0F;FRAM_ADDRESS = I2C1_SLAVE_ADDRESS7 | Addr;if (!I2C_Start() return FALSE; I2C_SendByte(FRAM_ADDRESS);/设置器件地址+段地址 if (!I2C_WaitAck()I2C_Stop();return FALSE; I2C_SendByte(count); /设置低起始地址 I2C_WaitAck(); I2C_Start(